ANILOX ROLL CLEANING BLANKET AND ASSEMBLY

Abstract

A micro-fibre anilox cleaning blanket having a cleaning surface area defined by a first pair of parallel edges located on opposing ends of the blanket and a second pair of edges that run between said end edges along either side of the blanket is provided. A connection strip is provided on each end edge of the blanket. The connection strips are configured to form non-permanent slotted relationships with complementary connection elements on print cylinder attachment means such that the blanket can be mounted on a print cylinder. Also provided is a system that includes a plurality of cleaning blankets and a variety of different types of print cylinder attachment means that can be combined to achieve a wide range of cleaning blanket assemblies that correspond to different print cylinder designs.

Claims

1-16. (canceled)

17. A micro-fibre anilox cleaning blanket, comprising: a cleaning surface area defined by a first pair of parallel edges located on opposing ends of the blanket and a second pair of edges that run between the first pair of parallel edges along either side of the blanket; and a connection strip provided to each of the first pair of parallel edges that is configured to form a non-permanent slotted relationship with a complementary connection element on a print cylinder attachment means such that the blanket can be mounted on a print cylinder.

18. The cleaning blanket of claim 17, wherein, when the blanket is laid flat, at least one of the second pair of edges comprises an angularly offset portion that is oblique to the first pair of parallel edges of the blanket.

19. The cleaning blanket of claim 18, wherein the angularly offset portion is located in the middle of each of the second pair of edges with the rest of each of the second pair of edges being perpendicular to the first pair of parallel edges.

20. The cleaning blanket of claim 19, wherein each perpendicular portion of each of the second pair of edges is between 2-3 mm long.

21. The cleaning blanket of claim 18, wherein each angularly offset portion is oriented at an angle of between 55 and 75? from one of the first pair of parallel edges of the blanket.

22. The cleaning blanket of claim 17, wherein each connection strip defines either a rib or a channel that runs along the length of its associated one of the first pair of parallel edges.

23. A micro-fibre anilox cleaning blanket assembly, comprising: at least one micro-fibre anilox cleaning blanket according to claim 17; and a plurality of print cylinder attachment means, each of which includes a print cylinder mounting element and a complementary blanket connection element, wherein each connection strip engages at least one complementary blanket connection element so as to form a non-permanent slotted relationship between the blanket and at least one of the plurality of print cylinder attachment means, thereby mounting the assembly on a print cylinder.

24. The assembly of claim 23, wherein the assembly comprises two or more cleaning blankets arranged adjacent one another such that their respective edges align to form a consolidated cleaning surface area.

25. The assembly of claim 24, wherein all of the connection strips along one of the first pair of parallel edges of the aligned blankets engage with the blanket connection element of a single common print cylinder attachment means.

26. The assembly of claim 24, wherein the connection strips on both of the first pair of parallel edges of the aligned blankets are engaged respectively with the blanket connection elements of common print cylinder attachment means.

27. The assembly of claim 24, wherein each blanket comprises at least one of the second pair of edges with an angularly offset portion and said portions are arranged in correspondence with one another so as to maintain a contiguous relationship between adjacent blankets thereby forming the consolidated cleaning surface area.

28. The assembly of claim 23, wherein the print cylinder attachment means comprise extension panels, tension bands and/or tension band clusters.

29. The assembly of claim 23, further comprising an underlay that supports the non-cleaning surface of the blanket and wherein the underlay either forms part of a print cylinder attachment means or is connectable thereto.

30. A micro-fibre anilox cleaning system, comprising: a plurality of micro-fibre anilox cleaning blankets according to claim 17; and a plurality of print cylinder attachment means, each of which includes a print cylinder mounting element and a complementary blanket connection element, wherein each connection strip engages at least one complementary blanket connection element so as to form a non-permanent slotted relationship between the blanket and the print cylinder attachment means that enables the plurality of micro-fibre anilox cleaning blankets to be mounted on a printed cylinder; and wherein the plurality of print cylinder attachment means comprises a range of print cylinder attachment means having a variety of print cylinder mounting elements configured to engage a plurality of different configurations of print cylinders.

31. The cleaning system of claim 30, wherein each of the cleaning surface areas of the plurality of cleaning blankets in the system differ from one another.

32. The cleaning system of claim 30, further comprising one or more underlays of different thickness that are selectable to adjust the overall thickness of the cleaning blanket assembly formed by the plurality of cleaning blankets and the plurality of print cylinder attachment means.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0045] FIG. 1a shows a diagrammatic representation of a flexographic printing press in operation in accordance with embodiments of the present invention;

[0046] FIG. 1b shows a diagrammatic representation of the printing press of FIG. 1a during the cleaning of the anilox roll with a cleaning blanket in accordance with embodiments of the present invention;

[0047] FIG. 2 shows a preferred embodiment of the cleaning blanket assembly in accordance with embodiments of the present invention;

[0048] FIG. 3 shows a second preferred embodiment of the cleaning blanket assembly in accordance with embodiments of the present invention; and

[0049] FIGS. 4a and 4b show the cleaning blanket assembly of FIG. 3 in two different size arrangements in accordance with embodiments of the present invention.

DETAILED DESCRIPTION

[0050] Before describing the present invention in more detail a brief overview of the operation and cleaning of anilox rolls will be provided with reference to FIGS. 1a and 1b. FIG. 1a shows a diagrammatic representation of a typical flexographic printing press 1 in a printing operation. The press 1 transfers ink 3 from a reservoir 2 to a substrate 9 (e.g. paper, cardboard) by way of a series of rolls.

[0051] The process begins with the fountain roll 4 collecting ink 3 from the ink reservoir 2 as it rotates through it. The ink 3 is then transferred to an anilox roll 5 as the fountain roll 4 and the anilox roll 5 are brought into close contact with one another. The surface of the anilox roll 5 is provided with an array of cells or channels in which the ink 3 is retained. Excess ink is removed from the anilox roll 5 by the action of a doctor blade 6.

[0052] As the anilox roll 5 continues to rotate the retained ink is brought into contact with a printing plate 8 that is mounted on a print cylinder 7 (also referred to as a plate cylinder). The printing plate 8 picks up the ink as it rotates past the anilox roll 5.

[0053] In the final printing stage the ink on the printing plate 8 is transferred to a substrate material 9 (e.g. paper, cardboard, or other flexible packaging materials). An impression cylinder 10 supports the substrate 9 in order to ensure the transfer of ink from the print plate 8 to the substrate and in so doing complete the printing of an image 11.

[0054] Over time the cells/channels of the anilox roll 5 can become clogged with dried ink 3a. The build-up of dried ink 3a reduces the capacity of the anilox roll 5 to pick up ink for transfer to the printing plate. This in turn can lead to an inconsistent application of ink to the printing plate 8, which reduces the quality of the final print image 11 delivered to the substrate.

[0055] In order to avoid such reductions in image quality it is necessary to clean the anilox roll 5 from time to time. The anilox roll can be removed from the printing press in order to clean it. However, as this can be time consuming and involves a risk of the roll being damaged during the dismantling process, it is generally more preferable to clean the anilox roll in situ; that is, without removing it from the printing press.

[0056] FIG. 1b shows an example of one in situ approach that is currently employed to clean anilox rolls 5. During cleaning the ink reservoir 2 is disengaged to prevent further ink being transferred to the anilox roll 5. The printing plate 8 is also removed from the print cylinder 7 and replaced with a cleaning blanket 12. The cleaning blanket is provided with a cleaning surface made up of an array of projecting micro-fibres.

[0057] During the cleaning operation the printing press is operated so as to rotate at least the anilox roll 5 and the print cylinder 7. By this method, and usually with the addition of cleaning detergents, the cleaning blanket acts like a scrubbing brush and removes the dried ink 3a from the cells/channels of the anilox roll 5.

[0058] Once the dried ink 3a has been removed from the anilox roll 5 the cleaning blanket 12 can be removed from the print cylinder and the printing plate 8 can be mounted once again. The printing press 1, so cleaned, is then ready to carry out a new printing run.

[0059] Although the general operational principles of flexographic printing presses are the same, there are currently a wide variety of different printing presses in operation, each of which has its own unique combination of characteristics (e.g. cylinder size, plate mounting systems and inter-cylinder clearances). As a result there is necessarily a correspondingly wide range of cleaning blankets configured to run on such printing presses.

[0060] This can create issues when multiple printing presses are in operation at a particular site due to the need to purchase and store multiple cleaning blankets and also the possibility of incorrect cleaning blankets being mounted by mistake.

[0061] The present invention seeks to address these problems by providing a universal cleaning blanket system that can be quickly and easily mounted to a range of different printing presses.

[0062] A first preferred embodiment is shown in FIG. 2 in the form of a micro-fibre anilox cleaning blanket assembly 20. The assembly 20 comprises a micro-fibre cleaning blanket 21 which is typically formed as an array of upright plastic bristles (e.g. polyester, nylon) that project from a rubber support substrate or mat.

[0063] As will be appreciated by the skilled person, the length and diameter of the bristles, as well as the overall bristle array density, can vary from one cleaning blanket to the next but essentially the bristles are configured to get into the ink cells/channels of the anilox roll during the cleaning process. However, by way of example, the micro-fibres bristles employed in the preferred embodiments are about 6 mm long.

[0064] In order to facilitate the mounting of the cleaning blanket assembly 20 on a print cylinder the end edges of the blanket 21 (i.e. both the leading edge and trailing edge when the blanket is mounted on a print cylinder) are provided with connection strips 22 and 24. In the preferred embodiment shown, the connection strips are retained in position by stitching 23 and 25. However it is envisaged that an alternative preferred fixing method involves the use of a suitable adhesive.

[0065] The connection strips 22 and 24, which are preferably plastic extrusions (e.g. PVC) that have either a male rib configuration or a female channel configuration, are positioned on the end edges such that a complementary print cylinder attachment means can be non-permanently slotted onto them. In the example shown, the connection strips 22 and 24 have a male rib configuration.

[0066] With reference to FIG. 2 it will be noted that print cylinder attachment means (i.e. tension bands 26) are only shown as being attached to one of the connection strips 24.

[0067] It will be understood by the skilled person that, in order for the cleaning blanket assembly 20 to be mounted on a print cylinder, connection strip 22 would also require print cylinder attachment means. However the print cylinder attachment means that would be used have been omitted from FIG. 2 in order to reveal the connection strip.

[0068] As noted above, the print cylinder attachment means provided on the connection strip 24 take the form of tension bands 26. It is envisaged that the tension bands 26 employed on the assembly 20 may be similar to those described in the applicant's earlier European Patent EP3112153.

[0069] In particular, each tension band 26 comprises a blanket connection element and a print cylinder mounting element joined by an elasticated strap. The cleaning blanket connection element is selected to be complementary to the connection strip (e.g. 24). As such the blanket connection element may take the form of either a female channel or a male rib.

[0070] However in the shown example, the tension bands are provided with a female channel to accommodate the male rib configuration of the connection strip 24.

[0071] It will be appreciated that the complementary nature of the connection strip and the cleaning blanket connection element allows each tension band 26 to form a non-permanent slotted relationship with the cleaning blanket 21, which in turn facilitates the mounting of the cleaning blanket assembly 20 on a print cylinder 7 using the print cylinder mounting elements of the tension bands.

[0072] As the print cylinder attachment means (i.e. 26) are not permanently connected to the cleaning blanket 21 the print technician has the option to quickly replace them with print cylinder attachment means that have different configurations. This flexibility allows the print technician to attach tension bands, for example, with a different type of print cylinder mounting element so that the cleaning blanket can be mounted onto a different design of print cylinder.

[0073] The print technician also has the option to employ different lengths of extension panels (e.g. see panel 34 in FIG. 3) on the cleaning blanket assembly, which in turn enables the blanket assembly to be used on cylinders with different diameters.

[0074] It is envisaged that even greater freedom of use is provided by the preferred embodiment shown in FIG. 3, which relates to a cleaning blanket assembly 30 that is formed from a pair of cleaning blankets 31, 32 rather than just a single micro-fibre blanket.

[0075] FIG. 3 shows a micro-fibre anilox cleaning blanket assembly 30 having a pair of micro-fibre cleaning blankets 31 and 32. Other than their shape, it is envisaged that the micro-fibre blankets have similar constructions.

[0076] As with the cleaning blanket 21 shown in FIG. 2, cleaning blankets 31 and 32 are provided with connection strips at each of their end edges (i.e. their leading and trailing edges). In particular, blanket 31 is provided with connection strips 33a and 38a, whereas blanket 32 is provided with connection strips 33b and 38b. Again, the connection strips are preferably stitched onto the blankets but alternative fixing methods may be employed without departing from the scope of the present invention.

[0077] As with the connection strips 22 and 24 shown in FIG. 2, the connection strips 33a, 33b, 38a, 38b shown in FIG. 3, which are preferably plastic extrusions (e.g. PVC) that has either a male rib configuration or a female channel configuration, are positioned on the end edges such that print cylinder attachment means can be non-permanently slotted onto the blanket assembly 30.

[0078] Each cleaning blanket 31, 32 constitutes a stand-alone separate component that can be handled separately. However, once the blankets have been aligned with one another they are secured together using the print cylinder attachment means, which in FIG. 3 take the form of extension panel 34 and tension band cluster 39.

[0079] The extension panel 34 comprises an elongate blanket connection element 36 and an elongate print cylinder mounting element 35 joined by a sheet of suitable plastic material 37 (e.g. polyesters such PET). The length of the sheet 37 can be selected to suit the length of cleaning blanket assembly that is needed for a particular design of print cylinder.

[0080] The tension band cluster 39 comprises an elongate blanket connection element 40 with a plurality of separate print cylinder mounting elements 41, each of which is joined to the elongate element by way of its own elasticated strap 42.

[0081] Specifically, with reference to FIG. 3, it will be appreciated that, once aligned, the connection strips 33a and 33b at the leading end edge of blankets 31, 32 are engaged by the blanket connection element 36 of the extension panel 34. At the trailing end edge of the blankets, the connection strips 38a and 38b are engaged by the blanket connection element 40 of the tension band cluster 39.

[0082] In this way the print cylinder attachment means (i.e. the extension panel 34 and the tension band cluster 39) serve a dual function of not only mounting the blankets onto a print cylinder but also retaining them in close alignment with one another so as to maintain a combined cleaning surface area.

[0083] By maintaining the blankets in close alignment with one another it is possible to create a cleaning blanket assembly that has a large cleaning surface area than might not otherwise be achievable due to the limitations associated with the manufacture of micro-fibre sheets.

[0084] It will be appreciated that in order for each pair of connections strips (i.e. 33a, 33b and 38a, 38b) to be received by a single common blanket connection element both connection strips need to be of the same type (i.e. male rib or female channel) so as to ensure a constant cross-section along the aligned connection strips.

[0085] It has been found that, even when multiple micro-fibre blankets are brought into alignment and retained in position by way of print cylinder attachment means, a gap can develop in the cleaning surface area of the cleaning blanket assembly 30. This gap has been exaggerated in FIG. 3 to highlight this issue.

[0086] Gaps in the cleaning surface area can lead to a cleaning dead zone where there are insufficient micro-fibre bristles to effectively clean the anilox roll. This incomplete cleaning of the anilox roll can create interference on the final print image due to the cells in a specific region of the anilox roll not being able to hold the same amount of ink as the rest of the cleaned anilox roll.

[0087] In order to avoid the creation of such cleaning dead zones the inventor found that the abutting side edges of neighbouring cleaning blankets could be provided with a sloped or slanted orientation. By adopting this arrangement it was possible to cause any gap to travel laterally across the anilox roll as cleaning process progressed. As a result, over time, every cell of the anilox roll would be brought into contact with the micro-fibre bristles and no cleaning dead zone would remain.

[0088] Although, in theory, the entire length of a blanket's side edge might be slanted, in practise it was found that positioning the angularly offset portion of each side edge between end portions that remain perpendicular to the end edges was beneficial. This was because the perpendicular portions provided a constant straight end edge onto which the connection elements could be attached (e.g. by stitching).

[0089] Although it is envisioned that these perpendicular portions could extend for any length along the abutting side edges of the blankets, increasing the length of these portions also increases the possibility that a cleaning dead zone may be created. Therefore, preferably each perpendicular portion runs for about 2-3 mm along the abutting side edge of each blanket.

[0090] The angularly offset portions of blanket side edges are preferably oriented at an angle (see 43 in FIG. 4) of between 55 and 75? from one of the end edges of the blanket. Also, in those embodiments where the side edge of the blanket has portions that are arranged perpendicular to the end edge of the blanket, it is envisioned that the angularly offset portions may be oriented at an angle of between 15 and 35? from such perpendicular portions.

[0091] Although not shown in the figures, it is envisaged that the various embodiments of the present invention may further be provided with an underlay below the micro-fibre cleaning blanket(s). Preferably the underlay comprises polyethylene foam. In this regard, underlays of different thicknesses could be employed to help further configure the cleaning blanket assembly to a particular design of printing press.

[0092] Preferably the underlays may also be configured to form non-slotted relationships with the cleaning blankets and/or the print cylinder attachment means on at least one of the end edges (such as the leading edge) of the blankets when they are mounted on a print cylinder.

[0093] FIGS. 4a and 4b show how the micro-fibre cleaning blanket assembly 30 of the preferred embodiment shown in FIG. 3 can be reconfigured for use on a larger print cylinder by interchanging one of the cleaning blankets 31 with a second, larger cleaning blanket 31a.

[0094] FIG. 4a shows a simplified representation of the assembly 30 shown in FIG. 3. The total length of the assembly, as achieved by aligning cleaning blankets 31 and 32 adjacent to one another, is a. In use, and as detailed above, the blankets would be held in alignment by the engagement of the complementary print cylinder attachment means to the end edges of the blankets.

[0095] In FIG. 4b, however, the total length of the assembly 30a has been increased to b by replacing original blanket 31 with alternative blanket 31a, which is identical to the original blanket 31 other that with respect to its width.

[0096] Although not shown, it will be appreciated that it would also be possible to achieve an assembly that is shorter in length than assembly 30 by replacing blanket 32 with blanket 31a.

[0097] It is envisaged that the cleaning blanket of the present invention makes it possible to provide a universal cleaning blanket system that, by way of selecting the appropriate combination of blankets and print cylinder attachment means (i.e. tension bands 26, extension panels 34, tension band clusters 40) a print technician can clean a wide variety of anilox rolls without the need to have a separate cleaning blanket for each printing press.