WO2015051000A1

WO2015051000A1 - A printing system and a printing kit for attachment to a flexographic printing cylinder

Info

Publication number: WO2015051000A1
Application number: PCT/US2014/058639
Authority: WO
Inventors: Yaroslav K. KHODATAEV; Alexey V. DMITRIEV; Alexey N. KLIMOV; Scott A. Van Wert
Original assignee: 3M Innovative Properties Company
Priority date: 2013-10-01
Filing date: 2014-10-01
Publication date: 2015-04-09
Also published as: RU2638501C2; RU2016111167A

Abstract

There is provides a printing system for attachment to a flexographic printing cylinder or a sleeve on a flexographic printing cylinder having a continuous first release liner and a self-adhesive damping layer for attaching the printing system to the cylinder or the sleeve. The self-adhesive damping layer is attached to the continuous first release layer, and the self-adhesive damping layer is composed of at least two separate parts with a different Shore A hardness. Also provided is a printing kit for attachment to a flexographic printing cylinder or a sleeve on a flexographic printing cylinder comprising the printing system and a printing plate.

Description

A PRINTING SYSTEM AND A PRINTING KIT FOR

ATTACHMENT TO A FLEXOGRAPHIC PRINTING CYLINDER

FIELD

The present disclosure generally relates to flexographic printing systems. In particular, the present disclosure relates to a printing system and a printing kit for attachment to a flexographic printing cylinder or a sleeve on a flexographic printing cylinder.

BACKGROUND

In the technology of flexographic printing special mounting tapes are usually used for attaching flexographic printing plates to a flexographic printing apparatus. In some cases printing plates include printing areas of different types (e.g. full-tone or process printing areas or non-printing areas, respectively) requiring mounting tapes with corresponding hardnesses a mounting tape with an average hardness acceptable for all such printing areas may be applied. However, in these cases the result does not always meet the requirements of the desired printing quality and printing accuracy.

A printing system disclosed in RU1 13994 eliminates some of the mentioned deficiencies. The printing system of RU1 13994 is a printing system for attachment to a flexographic printing cylinder comprising a printing plate with printing areas of different types and an attachment layer for attaching the printing system to the cylinder consisting of at least two separate parts having different values of hardness corresponding to the printing areas of the printing plate.

However, practical application of the mentioned printing system revealed in some instances an undesirable unpasting or detaching of the printing plate with the attachment layer from the printing cylinder due to insufficient adhesion parameters of the printing system. Furthermore, the labor-consuming and costly printing plate of the printing system attached to the printing cylinder cannot be reutilized in the event that the printing system is not positioned properly on the printing cylinder.

SUMMARY

In one aspect, the present disclosure provides a printing system for attachment to a flexographic printing cylinder or a sleeve on a flexographic printing cylinder having reliable adhesion quality for attaching to the cylinder or the sleeve and configured such that a printing plate can be reutilized in the case of inappropriate attachment of the printing system to the cylinder or the sleeve.

In some embodiments, the present disclosure provides a printing system for attachment to a flexographic printing cylinder or a sleeve on a flexographic printing cylinder, wherein the system comprises a continuous first release liner and a self-adhesive damping layer for attaching the printing system to the cylinder or the sleeve. The self-adhesive damping layer is attached to the continuous first release liner, and the self-adhesive damping layer is composed of at least two separate parts with a different Shore A hardness. The mentioned Shore A hardness is measured according to ASTM-D2240 in a direction normal to the self-adhesive damping layer.

By having the continuous first release liner such printing system can be efficiently attached to a flexographic printing cylinder without further undesirable unpasting or detaching from it. Besides, incorrect attachment of the printing plate to printing system does not damage the damping layer of the printing system attached to a flexographic printing cylinder.

According to some embodiments, at least one of the continuous first release liner and the self- adhesive damping layer comprises registration marks.

According to some embodiments, the continuous first release liner and the self-adhesive damping layer include registration marks such that positions of the corresponding registration marks of the continuous first release liner and the self-adhesive damping layer match each other. Such configuration of the registration marks provide accurate positioning of the printing system and a printing plate on a flexographic printing cylinder.

Preferably the continuous first release liner is a film that inherently has release properties, i.e. a low adhesion to the damping layer. Preferably the release liner is a transparent solid film.

According to some embodiments, the continuous first release liner comprises a substrate at least one surfaces of which is coated with a release layer comprising one or more silicones and/or other adhesion reducing compounds.

According to some embodiments, at least one of the surfaces of the continuous first release liner is coated by a continuous self-adhesive layer.

According to some embodiments, the surface of the self-adhesive damping layer that is not attached to the continuous first release liner is covered by a second release liner.

According to some embodiments, at least one of the surfaces of the self-adhesive damping layer is covered by a continuous self-adhesive layer. The continuous self-adhesive layer makes it possible to remove the printing system from the printing cylinder or reposition it on the printing cylinder while keeping the configuration of the separate parts of the self-adhesive damping layer.

In another aspect, the present disclosure also provides a printing kit for attachment to a flexographic printing cylinder or a sleeve on a flexographic printing cylinder. The printing kit comprises the above-described printing system and a printing plate having a first major surface and an opposite second major surface. The first major surface comprises printing and non-printing areas, said printing areas include at least one solid printing area and at least one process printing area corresponding to the at least two separate parts of the self-adhesive damping layer. The printing plate is configured to be attached to the cylinder or the sleeve after attaching the printing system to the cylinder or the sleeve and removing the continuous first release liner such that the at least one separate part having a higher Shore A hardness covers essentially all of the area on the second major surface of the printing plate corresponding to the at least one solid printing area, and the at least one separate part having a lower Shore A hardness covers at least part of the area on the second major surface of the printing plate corresponding to the at least one process printing area. The mentioned Shore A hardness is measured according to ASTM-D2240 in a direction normal to the self-adhesive damping layer.

The printing plate of the printing kit is configured to be attached to a flexographic printing cylinder or a sleeve on a flexographic printing cylinder of a flexographic printing apparatus by means of the printing system. To that effect the printing system is attached via the self-adhesive damping layer to the cylinder or the sleeve. The self-adhesive damping layer provides excellent adhesion parameters of the printing system attached to the flexographic printing apparatus. Then the continuous first release liner is removed thereby exposing the surface of the self-adhesive damping layer opposite to the flexographic printing apparatus. The printing plate is then attached to the exposed surface of the self-adhesive damping layer as is described above. Further, proper use of the labor-consuming and costly printing plate is also provided meaning that in case of incorrect positioning of the printing plate on the printing system repositioning of the printing plate on the printing system is possible without damage of the damping layer of the printing system and/or of the printing plate.

According to some embodiments, at least one of the continuous first release liner and the self- adhesive damping layer of the printing system comprises registration marks.

Preferably, the printing plate comprises registration marks, such that positions of the corresponding registration marks of the self-adhesive damping layer match the positions of the corresponding registration marks of the at least one of the continuous first release liner and the self- adhesive damping layer, accordingly. Correspondent registration marks on the components of the printing plate provide their accurate positioning on a flexographic printing apparatus.

In some embodiments, the continuous first release liner and the self-adhesive damping layer comprise registration marks such that positions of the corresponding registration marks of the continuous first release liner and the self-adhesive damping layer match each other.

According to some embodiments, the continuous first release liner is a film that inherently has a low adhesion to the damping layer and that comprises, for example, low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ultra low density polyethylene (ULDPE), enhanced polyethylene resin (EPE), polyvinyl chloride (PVC), ethylene-vinyl acetate copolymer (EVA), stretched polyethylene, oriented polypropylene films, ethylene/acid copolymer (EAA) or ethylene-vinvlalcohol (EVOH).

According to some embodiments, the continuous first release liner of the printing system is a transparent solid film optionally bearing a release coating.

According to some embodiments, the continuous first release liner comprises a film substrate made, for example, from polyester, paper and/or polyamide whereby at least one surface of such film is siliconized or treated otherwise to provide for a low adhesion between the continuous first release liner and the damping layer. According to some embodiments, at least one of the surfaces of the continuous first release liner is coated with a continuous self-adhesive layer.

According to some embodiments, the surface of the self-adhesive damping layer that is not fixed to the continuous first release liner is covered by a second release liner.

According to some embodiments, at least one of the surfaces of the self-adhesive damping layer is covered by a continuous self-adhesive layer.

According to some embodiments, the printing kit comprising at least one above described printing system corresponding to the printing plate wherein all printing systems of the printing kit are identical to each other. Additional identical printing systems can be used for replacing a damaged printing system due to, for example, incorrect positioning on a flexographic printing apparatus, without need of extra printing plates.

In yet another aspect, the present disclosure provides a flexographic printing system for attachment to a flexographic printing cylinder or a sleeve on a flexographic printing cylinder, where the system includes a continuous first release liner; and a first non-continuous self-adhesive damping layer for attaching the printing system to the cylinder or the sleeve, where the first non-continuous self- adhesive damping layer is attached to the continuous first release liner, and the first non-continuous self- adhesive damping layer is composed of a Shore A hardness; and at least one of the first non-continuous self-adhesive damping layer or continuous first release liner comprises registration marks; and one or more second self-adhesive damping layers, wherein the one or more second self-adhesive damping layers are continuous and shaped to fit pattern-wise within non-continuous regions of the first non-continuous self adhesive damping layer; and the one or more second self-adhesive damping layers has a different Shore A hardness than the first non-continuous self-adhesive damping layer; said Shore A hardness being measured according to ASTM-D2240 in a direction normal to the first non-continuous self-adhesive damping layer and the one or more second self-adhesive damping layers.

In some embodiments, one or more of the second self-adhesive damping layers is attached to a second release liner. In some embodiments, any of the self-adhesive damping layers can include registration marks to aide alignment of the second self-adhesive damping layers within the non- continuous regions of the one or more second self-adhesive damping layers.

In another aspect, the present disclosure provides a printing kit for attachment to a flexographic printing cylinder or a sleeve on a flexographic printing cylinder, said printing kit comprising: a printing system where the system includes a continuous first release liner; and a first non-continuous self-adhesive damping layer for attaching the printing system to the cylinder or the sleeve, where the first non- continuous self-adhesive damping layer is attached to the continuous first release liner, and the first non- continuous self-adhesive damping layer is composed of a Shore A hardness; and at least one of the first non-continuous self-adhesive damping layer or continuous first release liner comprises registration marks; and one or more second self-adhesive damping layers, wherein the one or more second self-adhesive damping layers are continuous and shaped to fit pattern-wise within non-continuous regions of the first non-continuous self adhesive damping layer; and the one or more second self-adhesive damping layers has a different Shore A hardness than the first non-continuous self-adhesive damping layer; said Shore A hardness being measured according to ASTM-D2240 in a direction normal to the first non-continuous self-adhesive damping layer and the one or more second self-adhesive damping layers, and a printing plate having a first major surface and an opposite second major surface where the first major surface comprises printing and non-printing areas, said printing areas comprising at least one solid printing area and at least one process printing area corresponding to the at least two separate parts of the self-adhesive damping layer, where the printing plate is configured to be attached to the cylinder or the sleeve after attaching the non-continuous damping layer of the printing system to the cylinder or the sleeve and removing the continuous first release liner, inserting the one or more second self-adhesive damping layers pattern-wise into the open areas of the non-continuous damping layer, and removing the second release liner such that the at least one separate part having a higher Shore A hardness covers essentially all of the area on the second major surface of the printing plate corresponding to the at least one solid printing area, and the at least one separate part having a lower Shore A hardness covers at least part of the area on the second major surface of the printing plate corresponding to the at least one process printing area, the Shore A hardness is measured according to ASTM-D2240 in a direction normal to the self-adhesive damping layer.

Further aspects, advantages and features of the present disclosure can be appreciated from the appended drawings and the description of the preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

Figs. 1 and 1A show schematic views of a printing system according to some embodiments of the present disclosure.

Figs. 2 and 2A show schematic views of a printing system according to some embodiments of the present disclosure.

Figs. 3A-3C show schematic views illustrating some embodiments of the printing system in which one of the surfaces of the self-adhesive damping layer or its both surfaces are covered by a continuous self-adhesive layer.

Fig. 4 shows a schematic view of a printing kit according to some embodiments of the present disclosure.

Figs. 5-5B show schematic views a printing system according to some embodiments of the present disclosure.

Figs. 6-6B show schematic views of a printing kit according to some embodiments of the present disclosure. DETAILED DESCRIPTION

A printing system for attachment to a flexographic printing cylinder or a sleeve on a flexographic printing cylinder of a flexographic printing apparatus can be used as a part of specialized materials for flexographic printing. The printing system comprises a continuous first release liner and a self-adhesive damping layer attached to the continuous first release liner.

The self-adhesive damping layer of the suggested printing system is produced before its attachment to a flexographic printing apparatus in accordance with the configuration of a printing plate to be attached on the same flexographic printing apparatus, and in this connection the suggested printing system can be called an intermediate printing system.

Among other things, the construction of the suggested printing system provides firm attachment with a flexographic printing apparatus without undesirable unpasting during the subsequent process of flexographic printing.

Printing plates that are used with the described printing system are ready-to-print printing plates obtained, for example, by imaging a precursor printing plate via a photopolymerization process. Precursor flexographic printing plates are commercially available, for example, as solid plates or sheeting, or they can be assembled at the time of imaging by casting a liquid photopolymer onto a polymeric carrier plate or sheeting.

The ready-to-print printing plate comprises printing areas (or imaged areas) and non-printing areas (or non-imaged) areas. The printing areas comprise solid (or full-tone) printing areas and process printing areas. The process printing area or areas, respectively, exhibit a relief image which is also referred to as plate relief in the art. The relief may comprise a multitude of microscopic structures such as, for example, dots or groups of raster points, text, reverses or strokes whereby the raster microscopic structures are typically not discernible from each other by the naked unaided eye when watching them from the distance of natural vision (30-40 cm). The solid printing areas do not comprise a relief structure and are preferably essentially unstructured. Both the process areas and solid areas, respectively, are of a macroscopic extension so that they can be readily visually discerned from each other.

In some modern embodiments the surface of solid printing areas of ready-to-print printing plate can have microscopic relief or texture specially designed to increase homogeneity and optical density of solid (or full-tone) printing. The depth of this microscopic relief is many times less than the depth of the relief image in process printing areas of printing plate. Printing plates with the microstructured solid printing areas and/or technologies for their production are commercially available for example under the trade designations of "KODAK DIGICAP", "DUPONT DIGIFLOW", "DUPONT DSP", "MACDERMID LUX", "FLINT NEXT" and others.

Printing plates can be manufactured, for example, by a usual technology including selective exposure of the non-printed precursor of the printing plate to ultraviolet radiation followed by removal of the non-polymerized photopolymer by washing out with solvents or by the thermal method. The one or more carrier layer(s), if present, bearing the photo-polymeric layer preferably are flexible. Suitable carrier layers can be made of suitable polymeric material (typically PET). The total thickness of the printing plate typically is between 0.76 mm and 7 mm and more preferably between 1.14 mm and 2.54 mm.

The damping layer is a self-adhesive layer compressible in a transverse direction that is used for applying an optimum printing pressure to printing areas of a printing plate such that the optimum printing pressure is higher in solid (full-tone) printing areas in comparison to process (relief) printing areas. Thus, the damping layer provides high printing quality and printing accuracy. The self-adhesive damping layer of the printing system preferably comprises one or more natural or synthetic rubbers that are preferably tackified, and/or one or more (meth)acrylates and can have two or more parts with different values of hardness. In particular, the self-adhesive damping layer includes at least two separate parts having different Shore A hardness as measured according to ASTM-D2240 in a direction normal to its surface, wherein:

at least one part of the damping layer having a relatively higher Shore A hardness corresponds to a solid printing area of the printing plate and covers essentially all of said area after the printing plate is attached to the printing system; and

at least one part of the damping layer having a relatively lower Shore A hardness corresponds to a process printing area of the printing plate and covers at least part of the said area after the printing plate is attached to the printing system.

The separate parts of the damping layer are preferably formed by two or more adhesive tapes having each a different Shore A hardness value depending on the structure of the respective process printing areas and shaped so that they can be arranged relative to each other in a snug fit. The gap between the separate parts of the damping layer has an average width that preferably is not more than 250 μηι and more preferably not more than 100 μηι so that a quasi-continuous damping layer is formed.

The adhesive tapes preferably comprise a carrier bearing on each side an adhesive layer and, in particular, a pressure-sensitive adhesive layer. These tapes are also referred to as double-sided adhesive tapes. It is also possible, however, to use a single-layer adhesive tape. In the double-sided adhesive tape the carrier preferably is a foam layer comprising a polymer and/or an adhesive matrix comprising hollow glass microspheres, at least partially expanded polymeric microspheres comprising a polymer shell encapsulating a gaseous atmosphere and/or excavations created by chemical blowing agents. The carrier is preferably flexible and can preferably be selected from a broad range of polymeric materials such as PET, polyethylene or polypropylene. The areas of the adhesive tape are attached via one of their respective major surfaces to the continuous first release liner in a snug fit thereby forming the printing system of the present utility model. The adhesive layers on the two major surfaces of the carrier of a specific double-sided adhesive tape may comprise the same adhesive each. In a preferred embodiment the adhesive layers of the double-sided adhesive tape are different from each other to optimize the adhesion properties such as peel or shear adhesion to the surface of a printing plate to be attached to the printing system and the surface of the printing cylinder or the sleeve, respectively. Commercially available double-sided adhesive tapes with a polymeric foam tape are preferred as damping layers. For example double-sided adhesive tapes with a polymeric foam tape are commercially available from 3M Co., St. Paul under the trade designation "CUSHION-MOUNT PLUS TAPES WITH EASY MOUNT ADHESIVE" (E series tapes) and under the designation "CUSHION-MOUNT PLUS EASY MOUNT TAPES WITH HIGH PLATESIDE ADEHSION" (E-H series tapes). The E-series comprises 19 different tapes having a Shore hardness of between 38 (El 060) and 72 (El 815 and El 820). The total thickness of the tapes varies between about 430 μιη (E1815, E1715, E1515, E1015, E1315, E1915, E1215 and El 1 15) and about 1,520 μιη (E1060). It is preferred to use E-series tapes of different Shore A hardness having essentially the same thickness. The second major surface of the adhesive tapes to be attached to the printing cylinder or the sleeve, respectively, is covered by a micro-structured liner forming micro-channels in the adhesive layer allowing air to escape from the interface between the tape and printing cylinder or sleeve, respectively. The E-H series comprises 19 different tapes having a Shore hardness of between 38 (E1060H) and 72 (E1815H and E1820H). The total thickness of the tapes varies between about 430 μηι (E1815H, E1715H, E1515H, E1015H, E1315H, E1915H, E1215H and E11 15H) and about 1,520 μιη (E1060H). The E-H series tapes exhibit a higher adhesion to the printing plate in comparison to the E series adhesives.

In some embodiments, it is preferable to use available commercial double-sided adhesive tapes with a polymeric foam tape as damping layers using their intended orientation of adhesive interfaces. For example, in some embodiments, it is preferable to use a double-sided adhesive tape with the intended printing plate adhesive face orientated to the non imaged surface of the printing plate.

The damping layer is preferably formed on a flat surface using, in particular, the working surface of a flatbed cutting plotter. Other flat surfaces can be used, however, as well. A great number of flatbed cutting plotters are presently on the market. Most flatbed cutting plotters are equipped with a flat working table that provides vacuum exhaust for fixation of a material such as an adhesive tape to be treated in progress of cutting. A suitable flatbed cutting plotter is commercially available from many suppliers such as Zund, Mimaki, Grahtec under the trade designation "ZUND M-1600", "MIMAKI CF-2", GRAPHTEC FC-2250", or similar.

Fig. 1 shows schematic views of a printing system 100 according to some embodiments of the present disclosure. The printing system 100 comprises a removable continuous first release liner 2 and a self-adhesive damping layer 3. In this embodiment a transparent solid film is used as the continuous first release liner 2 and the damping layer 3 includes two separate parts 4, 6 defined by different values of Shore A hardness, however the continuous first release liner 2 can be of any suitable form and the damping layer 3 can have more than two separate parts characterized by different values of Shore A hardness that is measured according to ASTM-D2240 in a direction normal to the self-adhesive damping layer.

In some embodiments, the damping layer 3 is made with a printing plate used for a particular flexographic printing pattern. For example, the separate parts of the damping layer 3 are prepared to correspond with configuration of printing areas on the printing plate such that when attaching the printing plate to the damping layer 3 the separate parts of the damping layer 3 with a higher value of Shore A hardness are covered by substantially all the surface of the printing areas corresponding to the so called solid printing area whereas the separate parts with a lower value of Shore A hardness are covered by at least part of the printing areas corresponding to the so called process printing area.

The Shore A hardness in the areas of the damping layer 3 corresponding to process printing areas is selected so as to provide optimal printing from such process printing areas. The Shore A hardness in such areas preferably has a Shore A hardness of between 50 and 65 and more preferably between 60 and 65. The Shore hardness in the areas of the damping layer 3 corresponding to solid printing areas preferably varies between 65 and 75 and more preferably between 68 and 72. The Shore A hardness in the areas of the damping layer 3 beneath a solid printing area or a process printing area after attaching a printing plate to the printing system, respectively, is preferably in each case constant and preferably varies in such areas, independently from each other, not more than 5 % and more preferably not more than 3 %.

In some embodiments of the present disclosure the Shore A hardness of the damping layer is lower in the process printing areas than the Shore A hardness of the solid printing areas. The difference between the average Shore A hardness value in at least one area of the damping layer corresponding to a solid printing area and at least one area corresponding to a process printing area is preferably at least 3 and more preferably at least 5.

Fig. 2 shows schematic views of a printing system 200 according to some embodiments of the present disclosure is identical to the printing system 100 except that the printing system 200 has registration marks. In particular, in the printing system 200 the continuous first release liner 22 comprises a registration mark 25 in the form of a registration dot and the self-adhesive damping layer 23 comprises a registration mark 26 in the form of a registration cut. Positions of the registration marks 25, 26 match each other to facilitate further registration of the separate parts of the damping layer 23 with the printing areas of the corresponding printing plate. Besides, registration marks 25, 26 were used during fabrication of the printing system 200.

The forms of the registration marks according to some embodiments of the present disclosure are given merely as an example and can be different in other embodiments; methods of their production can also vary in different embodiments and such methods are known for those skilled in the art. It shall be further noted that in some embodiments registration marks can be provided only in the continuous first release liner 22 or in the damping layer 23 on any of their surfaces in case of a registration dot. Registration marks can also be made as a print mark formed on a transparent adhesive sticker attached to the continuous first release liner 22 or the damping layer 23.

Preferably additional adhesion reductive release liners or adhesive layers are used for covering of the components of the printing layer according to the present disclosure. For example one or both of the surfaces of the continuous first release liner can be coated by an adhesion reductive release layer or by a continuous self-adhesive layer. Also the surface of the self-adhesive damping layer that is not fixed to the continuous first release liner can be covered by a second release liner.

Figs. 3A-3C illustrate possible embodiments of the printing system according to the present disclosure according to which one of the surfaces of the self-adhesive damping layer or its both surfaces are covered by a continuous self-adhesive layer. In particular, Fig. 3A schematically shows a printing system 510 in which a self-adhesive damping layer 503 is covered by a continuous self-adhesive layer 505 from the side of a continuous first release liner 502. Shown in Fig. 3B is a printing system 520 in which a self-adhesive damping layer 513 is covered by a continuous self-adhesive layer 515 on the side opposite to a continuous first release liner 512. Finally, Fig. 3C shows a printing system 530 in which two continuous self-adhesive layers 525 and 526 cover both sides of a self-adhesive damping layer 523, i.e. the side of the damping layer 523 fixed to a continuous first release liner 522 and the side of the damping layer 523 not fixed to the continuous first release liner 522. Usage of the continuous self-adhesive layers allows removing a printing system from a printing cylinder of a flexographic printing apparatus or repositioning a printing system on the printing cylinder without damaging the configuration of the separate parts of the self-adhesive damping layer.

The printing system according to the present disclosure is an intermediate system that is used with the corresponding printing plate. The present disclosure also provides a printing kit for attachment to a flexographic printing cylinder or a sleeve on a flexographic printing cylinder comprising the previously described printing system and a corresponding printing plate.

Fig. 4 shows a schematic view of a printing kit 300 according to some embodiments of the present disclosure. The printing kit 300 includes printing plate 1 10 and a printing system 120 according to the present disclosure comprising a continuous first release liner 32 and a self-adhesive damping layer 33 composed of at least two separate parts with a different Shore A hardness. In this embodiment the printing plate has only printing areas; however the printing plate 1 10 can also have non-printing areas. The printing areas of the printing plate 1 10 comprise at least one solid (full-tone) printing area 1 12 and at least one process (relief) printing area 1 13 (as described above, a relief printing area consists of raster microscopic structures that are typically not discernible from each other by the unaided eye). The self- adhesive damping layer 33 is fabricated on the basis of the digital source of the printing plate 1 10 to be attached to a flexographic printing cylinder such that the at least two separate parts of the layer 33 correspond to the at least one solid printing area 1 12 and at least one process printing area 1 13 of the printing plate 110 as described above. Specifically, when the printing plate 1 10 is being attached to the self-adhesive damping layer 33 of the printing system 120 the separate parts of the damping layer 33 with a higher value of Shore A hardness are covered by substantially all surface of the printing areas corresponding to the solid printing layer 1 12 and the separate parts with a lower value of Shore A hardness are covered by the at least part of the printing areas corresponding to the process printing area 1 13. The printing system 120 can have the registration marks and the additional adhesive layers as it was described above. Preferably, the surface of the self-adhesive damping layer 33 that is not fixed to the continuous first release liner 32 is covered by a second release liner. Also one or both of the surfaces of the self-adhesive damping layer 33 can be covered by a continuous self-adhesive layer. In addition, registration marks can also be fabricated on the printing plate 1 10. In this case preferably positions of the corresponding registration marks of the self-adhesive damping layer match the positions of the corresponding registration marks of the at least one of the continuous first release liner and the self- adhesive damping layer, accordingly.

When the printing kit 300 is used for flexographic printing initially the printing system 120 is attached to a flexographic printing cylinder or a sleeve on a flexographic printing cylinder of a flexographic printing apparatus preferably using the registration marks or cuts on printing system for precise positioning. Then the continuous first release liner 32 of the printing system 120 is removed and the printing plate 1 10 is attached on the cylinder or the sleeve preferably using the registration marks for precise positioning.

The printing kit 300 can include at least one additional printing system identical to the printing system 120. In case the original printing system 120 is damaged such identical printing systems can be used for replacing a damaged printing system.

Fig. 5 shows schematic views of a printing system 600 according to some embodiments of the present disclosure. The printing system component 600 comprises a removable continuous first release liner 612 and a first non-continuous self-adhesive damping layer 614. In some embodiments, a transparent solid film is used as the continuous first release liner 612 however the continuous first release liner 612 can be of any suitable form. In some embodiments, the presently disclosed printing system includes one or more components 610 having a removable continuous first release liner 618 and one or more second self-adhesive damping layers 616 as shown in Fig. 5B. In some embodiments a transparent solid film is used as the continuous first release liner 618 however the second release liner 618 can be of any suitable form. The printing system may include one or more components 610 comprising one or more second self-adhesive damping layers 616 that are continuous and shaped to fit pattern- wise within the one or more non-continuous regions of the first non-continuous self adhesive damping layer 614. The damping layers 614, 616 are characterized by different values of Shore A hardness that is measured according to ASTM-D2240 in a direction normal to the self-adhesive damping layers 614, 616.

The Shore A hardness in the areas of the damping layers 614, 616 corresponding to process printing areas is selected so as to provide optimal printing from such process printing areas. The Shore A hardness in such areas preferably has a Shore A hardness of between 50 and 65 and more preferably between 60 and 65. In some embodiments, the Shore hardness of the first non-continuous self-adhesive damping layer 614 or the one or more second self-adhesive damping layer 616 corresponding to solid printing areas preferably varies between 65 and 75 and more preferably between 68 and 72. In some embodiments, the Shore A hardness in the areas of the first non-continuous self-adhesive damping layer 614 or the one or more second self-adhesive damping layer 616 is preferably constant and vary independently from each other, not more than 5 % and more preferably not more than 3 %.

Referring now to Fig. 5A, in some embodiments, printing system 600 has registration marks 625, 626. Also one or both of the surfaces of the first non-continuous self-adhesive damping layer 614 can be covered by a continuous self-adhesive layer. In this case preferably positions of the corresponding registration marks 626 of the first non-continuous self-adhesive damping layer 614 match the positions of the corresponding registration marks 625 of continuous first release liner 612.

Fig. 6 shows a schematic view of a printing kit 700 according to some embodiments of the present disclosure. The printing kit 700 includes printing plate 730 and a printing system with components 710 and 720. The printing system component 710 comprises a removable continuous first release liner 712 and a first non- continuous self-adhesive damping layer 714. In some embodiments a transparent solid film is used as the continuous first release liner 712 however the continuous first release liner 712 can be of any suitable form. Referring to Fig. 6B, in some embodiments, the presently disclosed printing system includes one or more components 720 having a removable second release liner 718 and one or more second self-adhesive damping layers 716. In some embodiments, a transparent solid film is used as the second release liner 718 however the second first release liner 718 can be of any suitable form. As shown in Fig. 6A, the presently disclosed printing system may include one or more components 720 comprising one or more second self- adhesive damping layers 716 that are continuous and shaped to fit pattern- wise within the one or more non-continuous regions of the first non-continuous self adhesive damping layer 714. The damping layers 714, 716 are characterized by different values of Shore A hardness that is measured according to ASTM- D2240 in a direction normal to the self-adhesive damping layers 714, 716.

In some embodiments the printing plate 730 has only printing areas; however in some cases printing plates can also have non-printing areas. Exemplary printing areas of the printing plate 730 comprise at least one solid (full-tone) printing area 722 and at least one process (relief) printing area 723 (as described above, a relief printing area has raster microscopic structures that are typically not discernible from each other by the unaided eye).

Referring now to Fig. 6B, a self-adhesive damping layer 733 includes first non-continuous self- adhesive damping layer 714 and one or more second self-adhesive damping layers 716. In some embodiments, the at least one solid printing area 722 is placed adjacent to the one or more second self- adhesive damping layers 716. In some embodiments, the at least one process printing area 733 is positioned adjacent to first non-continuous self-adhesive damping layer 714. Specifically, when the printing plate 730 is being attached to the self-adhesive damping layer 733 of the printing system, the one or more second self-adhesive damping layers 716 have a higher value of Shore A hardness than the Shore A hardness of the first non-continuous self-adhesive damping layer 714.

In some embodiments, component 710 of the presently disclosed printing system has registration marks 725, 726 and an additional adhesive layers as it was described above with respect to Fig. 6. Also one or both of the surfaces of the self-adhesive damping layer 733 can be covered by a continuous self- adhesive layer. In addition, registration marks can also be fabricated on the printing plate 730. In this case preferably positions of the corresponding registration marks 726 of the first non-continuous self-adhesive damping layer 714 match the positions of the corresponding registration marks 725 of continuous first release liner 712.

When the printing kit 700 is initially used for flexographic printing, component 710 of the printing system is attached to a flexographic printing cylinder or a sleeve on a flexographic printing cylinder of a flexographic printing apparatus preferably using registration marks or cuts 726, 725 on printing system for precise positioning. Then the continuous first release liner 712 of component 710 is removed. Then component 720 of the printing system is inserted pattern-wise into the one or more non- continuous regions of the first non-continuous self-adhesive damping layer 714 so that the second release liner 718 can be removed. Second release liner 718 is removed and the printing plate 730 is then attached on the cylinder or the sleeve having the self-adhesive layer 733 therebetween. It is preferable to use registration marks on the printing plate 730 for precisely positioning the presently disclosed printing kit 700.

In some embodiments, there can be multiple printing systems included in the printing kit 700 in which the multiple printing systems include components 710 and 720, which can all be configured the same or different. In case the original printing system 700 is damaged identical printing system components 710, 720 can be used for replacing a damaged printing system.

The present disclosure provides the following non-limiting, exemplary embodiments:

Embodiment 1. A printing system for attachment to a flexographic printing cylinder or a sleeve on a flexographic printing cylinder, wherein the system comprises:

a continuous first release liner ; and

a self-adhesive damping layer for attaching the printing system to the cylinder or the sleeve, wherein at least one of the continuous first release liner and the self-adhesive damping layer comprises registration marks,

and further wherein the self-adhesive damping layer is attached to the continuous first release liner, and the self-adhesive damping layer is composed of at least two separate parts with a different Shore A hardness,

said Shore A hardness being measured according to ASTM-D2240 in a direction normal to the self-adhesive damping layer.

Embodiment 2. The printing system according to Embodiment 1, wherein the continuous first release liner and the self-adhesive damping layer comprise registration marks such that positions of the corresponding registration marks of the continuous first release liner and the self-adhesive damping layer match each other.

Embodiment 3. The printing system according to any of the preceding Embodiments, wherein the continuous first release liner is a transparent solid film. Embodiment 4. The printing system according to any of the preceding Embodiments, wherein the release liner comprises a substrate at least one of surfaces of each is coated with release layer comprising one or more silicones and/or other adhesion reducing compound.

Embodiment 5. The printing system according to any of the preceding Embodiments, wherein at least one of the surfaces of the continuous first release liner is coated by a continuous self-adhesive layer.

Embodiment 6. The printing system according to any of the preceding Embodiments, wherein the surface of the self-adhesive damping layer that is not fixed to the continuous first release liner is covered by a second release liner.

Embodiment 7. The printing system according to any of the preceding Embodiments, wherein at least one of the surfaces of the self-adhesive damping layer is covered by a continuous self-adhesive layer.

Embodiment 8. A printing kit for attachment to a flexographic printing cylinder or a sleeve on a flexographic printing cylinder, said printing kit comprising:

the printing system according to any of the preceding claims; and

a printing plate having a first major surface and an opposite second major surface wherein the first major surface comprises printing and non-printing areas, said printing areas comprising at least one solid printing area and at least one process printing area corresponding to the at least two separate parts of the self-adhesive damping layer,

wherein the printing plate is configured to be attached to the cylinder or the sleeve after attaching the printing system to the cylinder or the sleeve and removing the continuous first release liner such that the at least one separate part having a higher Shore A hardness covers essentially all of the area on the second major surface of the printing plate corresponding to the at least one solid printing area, and the at least one separate part having a lower Shore A hardness covers at least part of the area on the second major surface of the printing plate corresponding to the at least one process printing area,

Embodiment 9. The printing kit according to Embodiment 8, wherein the printing plate comprises registration marks, such that positions of the corresponding registration marks of the self-adhesive damping layer match the positions of the corresponding registration marks of the at least one of the continuous first release liner and the self-adhesive damping layer, accordingly.

Embodiment 10. The printing kit according to Embodiment 8, wherein the continuous first release liner and the self-adhesive damping layer comprise registration marks such that positions of the corresponding registration marks of the continuous first release liner and the self-adhesive damping layer match each other.

Embodiment 1 1. The printing kit according to Embodiments 8 to 10, wherein the continuous first release liner of the printing system is a film having a low adhesion to the damping layer, the continuous first release liner comprising at least one material from the group of materials including low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ultra low density polyethylene (ULDPE), enhanced polyethylene resin (EPE), polyvinyl chloride (PVC), ethylene-vinyl acetate copolymer (EVA), stretched polyethylene, oriented polypropylene films, ethylene/acid copolymer (EAA) and ethylene- vinvlalkohol (EVOH).

Embodiment 12. The printing kit according to claim Embodiment, wherein the continuous first release liner of the printing system is a transparent solid film.

Embodiment 13. The printing kit according to claim Embodiment 8, wherein the release liner comprises a film substrate made at least one of polyester, paper and polyamide, wherein at least one surface of the film is siliconized.

Embodiment 14. The printing kit according to any of Embodiments 8 to 13, wherein at least one of the surfaces of the continuous first release liner is coated with a continuous self-adhesive layer.

Embodiment 15. The printing kit according to any of Embodiments 8 to 14, wherein the surface of the self-adhesive damping layer that is not fixed to the continuous first release liner is covered by a second release liner.

Embodiment 16. The printing kit according to any of Embodiments 8 to 15, wherein at least one of the surfaces of the self-adhesive damping layer is covered by a continuous self-adhesive layer.

Embodiment 17. The printing kit according to any of Embodiments 8 to 16, further comprising at least one printing system according to claim 1 corresponding to the printing plate wherein all printing systems of the printing kit are identical to each other.

Embodiment 18. A flexographic printing system for attachment to a flexographic printing cylinder or a sleeve on a flexographic printing cylinder, wherein the system comprises:

a continuous first release liner ; and

a first non-continuous self-adhesive damping layer for attaching the printing system to the cylinder or the sleeve,

wherein the first non-continuous self-adhesive damping layer is attached to the continuous first release liner, and the first non-continuous self-adhesive damping layer is composed of a Shore A hardness; and

at least one of the first non-continuous self-adhesive damping layer or continuous first release liner comprises registration marks; and

one or more second self-adhesive damping layers,

wherein the one or more second self-adhesive damping layers are continuous and shaped to fit pattern- wise within non-continuous regions of the first non-continuous self adhesive damping layer; and the one or more second self-adhesive damping layers has a different Shore A hardness than the first non-continuous self-adhesive damping layer ;

said Shore A hardness being measured according to ASTM-D2240 in a direction normal to the first non-continuous self-adhesive damping layer and the one or more second self-adhesive damping layers. Embodiment 19. The flexographic printing system according to Embodiment 18, wherein the one or more second self-adhesive damping layers is attached to a second release liner.

Embodiment 20. The flexographic printing system according to Embodiment 18 or 19, wherein any of the self-adhesive damping layers comprise registration marks to aide alignment of the second self- adhesive damping layers within the non-continuous regions of the one or more second self-adhesive damping layers.

Embodiment 21. A printing kit for attachment to a flexographic printing cylinder or a sleeve on a flexographic printing cylinder, said printing kit comprising:

the printing system according to Embodiment 18; and

wherein the printing plate is configured to be attached to the cylinder or the sleeve after attaching the non-continuous damping layer of the printing system to the cylinder or the sleeve and removing the continuous first release liner, inserting the one or more second self-adhesive damping layers pattern-wise into the open areas of the non-continuous damping layer, and removing the second release liner such that the at least one separate part having a higher Shore A hardness covers essentially all of the area on the second major surface of the printing plate corresponding to the at least one solid printing area, and the at least one separate part having a lower Shore A hardness covers at least part of the area on the second major surface of the printing plate corresponding to the at least one process printing area,

The present disclosure is not limited to the previously disclosed embodiments and covers all modifications and alternatives coming within the scope and spirit of the present disclosure. The disclosed embodiments are intended to be illustrative and may be varied in different ways and such variations are not to be considered as a departure from the spirit and scope of the present disclosure. Every embodiment derived from a combination of technical means disclosed in different embodiments is also intended to be included within the scope of the following claims.

Claims

WHAT IS CLAIMED IS:

1. A printing system for attachment to a flexographic printing cylinder or a sleeve on a flexographic printing cylinder, wherein the system comprises:

a continuous first release liner ; and

2. The printing system according to claim 1, wherein the continuous first release liner and the self-adhesive damping layer comprise registration marks such that positions of the corresponding registration marks of the continuous first release liner and the self-adhesive damping layer match each other.

3. The printing system according to any of the preceding claims, wherein the continuous first release liner is a transparent solid film.

4. The printing system according to any of the preceding claims, wherein the release liner comprises a substrate at least one of surfaces of each is coated with release layer comprising one or more silicones and/or other adhesion reducing compound.

5. The printing system according to any of the preceding claims, wherein at least one of the surfaces of the continuous first release liner is coated by a continuous self-adhesive layer.

6. The printing system according to any of the preceding claims, wherein the surface of the self- adhesive damping layer that is not fixed to the continuous first release liner is covered by a second release liner.

7. The printing system according to any of the preceding claims, wherein at least one of the surfaces of the self-adhesive damping layer is covered by a continuous self-adhesive layer.

8. A printing kit for attachment to a flexographic printing cylinder or a sleeve on a flexographic printing cylinder, said printing kit comprising:

the printing system according to any of the preceding claims; and

9. The printing kit according to claim 8, wherein the printing plate comprises registration marks, such that positions of the corresponding registration marks of the self-adhesive damping layer match the positions of the corresponding registration marks of the at least one of the continuous first release liner and the self-adhesive damping layer, accordingly.

10. The printing kit according to claim 8, wherein the continuous first release liner and the self- adhesive damping layer comprise registration marks such that positions of the corresponding registration marks of the continuous first release liner and the self-adhesive damping layer match each other.

1 1. The printing kit according to claims 8 to 10, wherein the continuous first release liner of the printing system is a film having a low adhesion to the damping layer, the continuous first release liner comprising at least one material from the group of materials including low density polyethylene (LDPE), linear low density polyethylene (LLDPE), ultra low density polyethylene (ULDPE), enhanced polyethylene resin (EPE), polyvinyl chloride (PVC), ethylene-vinyl acetate copolymer (EVA), stretched polyethylene, oriented polypropylene films, ethylene/acid copolymer (EAA) and ethylene -vinvlalkohol (EVOH).

12. The printing kit according to claim 8, wherein the continuous first release liner of the printing system is a transparent solid film.

13. The printing kit according to claim 8, wherein the release liner comprises a film substrate made at least one of polyester, paper and polyamide, wherein at least one surface of the film is siliconized.

14. The printing kit according to any of claims 8 to 13, wherein at least one of the surfaces of the continuous first release liner is coated with a continuous self-adhesive layer.

15. The printing kit according to any of claims 8 to 14, wherein the surface of the self-adhesive damping layer that is not fixed to the continuous first release liner is covered by a second release liner.

16. The printing kit according to any of claims 8 to 15, wherein at least one of the surfaces of the self-adhesive damping layer is covered by a continuous self-adhesive layer.

17. The printing kit according to any of claims 8 to 16, further comprising at least one printing system according to claim 1 corresponding to the printing plate wherein all printing systems of the printing kit are identical to each other.

18. A flexographic printing system for attachment to a flexographic printing cylinder or a sleeve on a flexographic printing cylinder, wherein the system comprises:

a continuous first release liner ; and

one or more second self-adhesive damping layers,

said Shore A hardness being measured according to ASTM-D2240 in a direction normal to the first non-continuous self-adhesive damping layer and the one or more second self-adhesive damping layers.

19. The flexographic printing system according to claim 18, wherein the one or more second self- adhesive damping layers is attached to a second release liner.

20. The flexographic printing system according to claim 18 or 19, wherein any of the self- adhesive damping layers comprise registration marks to aide alignment of the second self-adhesive damping layers within the non-continuous regions of the one or more second self-adhesive damping layers.

21. A printing kit for attachment to a flexographic printing cylinder or a sleeve on a flexographic printing cylinder, said printing kit comprising:

the printing system according to claim 18; and