Anilox roller, printing unit with anilox roller and method for producing an anilox roller

Abstract

The invention relates to an anilox roller, wherein at least one fluid coating material can be applied to the anilox roller from at least one reservoir and the coating material can be transferred from the anilox roller to at least one receiving element, wherein the surface (21) of the casing surface of the anilox roller has a plurality of depressions (25, 27, 29) for at least periodically receiving the coating material, wherein at least two depressions (25, 27, 29) are also fluidically connected by means of at least one connecting channel (35) formed in the surface (21) and / or below the surface (21) of the casing surface, as well as a printing unit and a method for producing an anilox roller.

Description

[0001] Anilox roller, printing unit with anilox roller and method for manufacturing an anilox roller

[0002] DESCRIPTION

[0003] The present invention relates to an anilox roller, in particular anilox roller, for at least one printing unit, in particular anilox and / or flexographic printing unit, and to a printing unit comprising at least one such anilox roller.

[0004] Such printing units are particularly well-known from offset newspaper printing or waterless offset printing for the production of printed documents. They are also increasingly being used in the manufacturing processes of electrical storage devices such as batteries, accumulators, capacitors, electrolyzers, and the like. These printing units enable continuous processing compared to the sequential or serial processing of individual components. This increases throughput and production speed. Processing speeds of 300 m / min and more are desired. Components of the electrical storage device, which can be manufactured from windable materials such as films, optionally plastic and / or metal foils, are coated using these printing units, for example, with a pre-coating to increase the adhesion of other elements applied to the material.Such printing devices also enable the application of high layer thicknesses in a single coating step.

[0005] Due to the use of coated materials in electronic memory, these materials must meet extremely high quality requirements, particularly regarding uniformity, layer thickness, accuracy of coated surface boundaries, and / or contamination of areas not to be coated. This places significantly higher quality demands on the printing units in conjunction with the anilox roller for use in this technical field compared to printing units used in literature or color printing.

[0006] However, the production of electrical storage components, such as battery foil manufacturing, requires intermittent coating. In this coating process, the coating material is applied intermittently to a substrate around a roller, with each coated area followed by an uncoated area.

[0007] Such a coating is very difficult to achieve in a slot coating process, if at all, because it is a casting process and therefore the edge smoothing cannot be properly controlled, resulting in tear edges.

[0008] In contrast, the coating area can be selected very precisely using the aniolox or gravure printing process.

[0009] Slot coating allows for continuous coating, where a low-viscosity coating material is applied to the substrate through a narrow slit or "slot" opening. However, as mentioned, the edge formation is not achievable with the necessary quality.

[0010] In gravure printing, a direct printing process is used, in which the coating material (in the case of literature print products, the ink) is transferred from a printing plate formed by the indentation in the anilox roller to the substrate, enabling mass production. Furthermore, gravure printing offers the advantages necessary for the production of electronic memory components: high print quality with high application rates, due to the aforementioned high-volume screen geometry, uniform distribution of the coating material over large areas, and the ability to coat precisely defined areas.

[0011] Especially at the desired processing speeds of 300 m / min and above, effects not previously observed in the production of printed literature occur, leading to enormous and unacceptable losses in quality. This is particularly true when these processing speeds are combined with large-volume jobs, i.e., jobs with volumes of, for example, 75-80 cm³. 3 / m 2 in the case of a wet application, which for example corresponds to a layer thickness of approximately 22.3 m or an application weight of 60-70 g / m² 2 Further challenges arise when the coating material corresponds to the substrate material.

[0012] Of particular note here is the so-called pumping effect. When the coating material is applied to the anilox roller, air becomes trapped within the material as it is transferred from the reservoir, such as a doctor blade chamber, to the roller. This necessitates high rotational speeds of the printing unit and, consequently, of the anilox roller, to achieve high processing speeds. These high rotational speeds lead to increased vibrations between the reservoir and the anilox roller, resulting in uneven application of the coating material to the roller.

[0013] Due to the high machine speeds and large-volume application, a minimal amount of air is forced into the individual cells (holes) of the anilox roller, particularly during the printing process at the reservoir in the printing unit. This air expands rapidly after the doctor blade passes and escapes from the cell. This leads to spatter and / or bubbles. These bubbles subsequently appear as irregularities on the substrate. In other words, foaming can occur.

[0014] Furthermore, due to this so-called pumping effect, a vibration occurs at the doctor blade when using a doctor blade chamber, which increases or intensifies the spattering effect, bubble formation and foam formation in the doctor blade chamber or ink tray, and can also generate vibrations that can damage the anilox roller.

[0015] It is known in the art to add additives to the coating material. These can be antifoaming agents, i.e., substances that form a closed film, particularly at a fluid interface, which accelerates outgassing or enables outgassing by destroying gas bubbles, in order to influence the properties of the coating material as desired, especially to reduce the effects described above. However, the addition leads to a reduction in processing speed or increased production costs. Therefore, the corresponding additives must be removed from the printed product before further processing, for example, by heat treatment.

[0016] Attempts have also been made to avoid or at least reduce this pumping effect by using special coatings on the anilox roller, such as Teflon coatings. However, these measures have also failed to produce the desired quality improvements.

[0017] It is therefore an object of the present invention to provide an anilox roller and a printing unit that enables the production of high-quality components for electrical storage devices, in particular eliminating or at least reducing the pumping effect.

[0018] This problem is solved with respect to the anilox roller by an anilox roller, wherein at least one fluid coating material can be applied to the anilox roller from at least one reservoir and the coating material can be transferred from the anilox roller to at least one receiving element, wherein the surface of the anilox roller's outer surface has a plurality of depressions for at least temporarily receiving the coating material, and wherein at least two depressions are fluidically connected by means of at least one connecting channel formed in the surface and / or below the surface and / or the outer surface.

[0019] It is preferred that the coating material comprises at least a high-viscosity battery material, at least a slurry coating material, at least a suspension, at least one, in particular chemical, active material, preferably of a battery, and / or at least a high-viscosity coating material, preferably for coatings in the EIFC area.

[0020] It may also be provided that the reservoir includes at least one doctor blade and / or at least one chamber doctor blade.

[0021] An anilox roller can be characterized in that the receiving element comprises at least one further roller and / or at least one support material. It is particularly preferred that the support material comprises at least one windable material, at least one flexible material, at least one film, at least one component of an electrical storage device, and / or at least one support material usable in a component of an electrical storage device, wherein the electrical storage device optionally comprises and / or at least partially forms at least one battery, accumulator, capacitor, electrolyzer, wet cell, flow battery, and / or redox flow battery.

[0022] It is also proposed that at least one depression includes at least one cup, at least one hash, at least one pyramidal depression, at least one trough-shaped depression, at least one dome-shaped depression and / or at least one truncated pyramidal depression and / or that the depression has at least partially a rectangular, square, pentagonal, triangular, hexagonal, circular, octahedral and / or elongated cross-section, in particular opening cross-section and / or bottom cross-section, and / or that several depressions form at least partially a uniform and / or geometric pattern, such as a "Penrose" grid.

[0023] Preferred embodiments provide that the anilox roller is rotatable at least about one axis of rotation, wherein the recesses connected by the connecting channel are arranged at least partially offset about the axis of rotation and / or the connecting channel has at least one directional component in the circular direction and / or circumferential direction of the axis of rotation.

[0024] Finally, it is proposed that the indentation on the anilox roller be created by means of laser etching and / or direct laser ablation.

[0025] With regard to the printing unit, this problem is solved by a printing unit comprising at least one anilox roller according to the invention, in particular as described above.

[0026] For the printing unit, it is proposed that the printing unit includes at least one reservoir for at least one fluid coating material, with the reservoir optionally being in operative contact with the anilox roller at least indirectly for the transfer of the coating material to the anilox roller.

[0027] It is also preferred that at least one further roller is in operative contact with the anilox roller, wherein the anilox roller and the further roller preferably roll against each other.

[0028] Furthermore, it may be provided that at least one carrier material which can be coated and / or is to be coated with the coating material, at least in certain areas, can be supplied to the anilox roller and / or the other roller.

[0029] Furthermore, the invention provides a method for manufacturing an anilox roller, in particular an anilox roller according to the invention, preferably as described above, wherein the method comprises providing a roller with a cylindrical surface and forming a grid of depressions on the surface of the roller, wherein forming the grid comprises (i) forming at least two depressions which are connected to each other by at least one connecting channel and / or (ii) forming the depressions by means of laser etching and / or direct laser ablation.

[0030] The invention is thus based on the surprising finding that by forming a grid with depressions on an anilox roller, in which the individual depressions are interconnected like cells, any trapped air during the coating material application process can escape from the respective depression into the depression connected by the connecting channel. This minimizes the described pumping effect and also reduces vibration at the doctor blade. Furthermore, the grid geometry results in a smoother application of the coating material to the substrate. Preferably, the interconnected depressions are arranged at different circular positions in the circumferential direction of the anilox roller, particularly in the machine direction of the gravure printing press.This ensures that the air can escape freely from the connected recess, particularly if the connected recess is not covered at all or not completely, for example by the doctor blade and / or the coating material in the reservoir. The air can escape through this at least partially uncovered area.

[0031] Furthermore, the arrangement of the recesses in the grid ensures a high degree of uniformity of the coating material on the receiving element, particularly on the substrate. In particular, it prevents, or at least reduces, the foaming of the coating material that leads to irregularities.

[0032] Furthermore, due to the minimization of air inclusions, vibration of a doctor blade during the process is suppressed, or at least reduced, thus ensuring a more uniform application of the medium onto the receiving element, such as the carrier material or another roll.

[0033] Preferably, the depressions are laser-etched or produced by direct laser ablation to create the halftone structures in the anilox roller, optionally for a gravure printing unit and / or anilox printing unit, whereby the halftone pattern is formed by recessed and raised elements.

[0034] With laser-etched engraving, optionally with a hexagonal grid, a maximum theoretical fill volume of 200 cm³ is possible. 3 / m 2 This can be achieved, resulting in a wet application of 75-80 cm with a maximum emptying of the reservoir in the process of 40%. 3 / m 2This leads to a situation where, in contrast, electromechanical engraving can only achieve a maximum theoretical fill volume of 50 cmVm. 2 This can be achieved, resulting in a wet application of max. 19-20 cm. 3 / m 2 This results in a layer thickness of approximately 5.8 pm.

[0035] Further features and advantages of the invention will become apparent from the following description, in which preferred embodiments are explained with reference to the accompanying figures.

[0036] This shows

[0037] Fig. 1 is a schematic representation of a printing unit according to the invention with an anilox roller according to the invention; Fig. 2a is a top view of a first embodiment of a printing unit according to the invention.

[0038] Anilox roller;

[0039] Fig. 2b shows a detailed view of section A of the anilox roller of Fig. 2a;

[0040] Fig 3a shows a top view of a second embodiment of an invention.

[0041] Anilox roller;

[0042] Fig. 3b shows a detailed view of section B of the anilox roller of Fig. 3a; and

[0043] Fig. 4a - 4c Process steps of a laser etching engraving for producing a raster pattern on an anilox roller according to the invention.

[0044] Fig. 1 shows the schematic structure of a printing unit 1 according to the invention. The printing unit 1 is designed as a calender and includes a reservoir 3 for receiving a coating material 5. In this example, the reservoir 3 is designed as a chambered doctor blade. As explained below, the printing unit 1 is used to coat a substrate 7 for the production of electrical storage elements. For this purpose, different coating materials such as glue, varnish, primer, or the like are applied by means of the printing unit 1, depending on requirements. Compared to printing inks used in printing units for printing on paper, such coating materials exhibit significantly different properties, such as viscosity, basis weight, pigment size, pigment concentration, composition, flow behavior, and / or drying behavior.

[0045] For coating the substrate material 7, such as a plastic film or metal foil, such as copper foil, the coating material 5 is transferred to an anilox roller 11 according to the invention by means of the chambered doctor blade 3, in particular a doctor blade 9 encompassed by the reservoir 3.

[0046] By rotating the anilox roller 11 about the axis of rotation 13, the coating material 5 is transferred to a receiving element, here in the form of a transfer roller 15 rotating in the opposite or opposite direction to the anilox roller 11. The coating material 3 is then applied to the substrate 7. This substrate passes through a gap between the transfer roller 15 and a pressure roller 17.

[0047] To define the areas of the substrate 7 onto which the coating material 5 is applied, the anilox roller 11 has a grid pattern 23 on its surface. This grid pattern 23 comprises depressions or cups in which the coating material is received. These depressions are thus arranged in the areas where the coating material 5 is to be applied to the substrate 7, while the areas of the anilox roller 11 that do not have depressions remain free of coating material, so that corresponding areas of the substrate 7 remain free of coating material 5. In particular, any coating material 5 adhering to these areas is wiped off by the doctor blade 9.

[0048] As already mentioned, the production of electrical storage devices involves the use of coating materials 3 with significantly different properties compared to printing inks. These materials have an increased tendency to develop air inclusions and foaming during the transfer of the coating material 3 to the anilox roller. This pumping effect, already described in the introduction, leads to considerable problems and significantly limits throughput rates and production speed.

[0049] To overcome, or at least reduce, the pumping effect, the invention proposes a special type of rasterization of the anilox roller 11. Furthermore, this rasterization is preferably produced by laser etching engraving to further improve the quality of the coating on the substrate.

[0050] Fig. 2a shows a side view of an anilox roller 11 according to the invention. The anilox roller 11 is rotatably mounted about the axis of rotation 13 via bearings 19.

[0051] Figure 2b shows a detailed view of section A of the anilox roller 11 according to a first embodiment. Figure 2b shows the outer surface of the anilox roller 11 in section A. As can be seen in Figure 2b, the surface 21 of the anilox roller 11 has a grid pattern 23. This grid pattern 23 is formed by depressions 25, 27, 29. In this embodiment, the depressions 25, 27, 29 have a hexagonal opening cross-section. Between the depressions 25, 27, 29, raised sections in the form of ridges 31 are formed, the surface of which lies at the same height as the remaining surface 21 of the anilox roller 11, in which no depressions are formed.

[0052] In Fig. 2a, the anilox roller 11 is further shown in a position in which the doctor blade 9 rests on the surface 21 of the anilox roller 11 in position 33.

[0053] According to the invention, the screen 23 is characterized by the fact that connecting channels 35 are formed between individual recesses. The connecting channel 35 between recesses 27 and 29 is given as an example. The connecting channel 35 runs essentially along or parallel to a circumferential direction Z and perpendicular to a longitudinal direction L of the anilox roller 11. The longitudinal direction L runs parallel to the axis of rotation 13.

[0054] In embodiments not shown, the connecting channel can also run in a different direction relative to the longitudinal direction L and the circumferential direction Z. However, as explained below, it is preferred that the connecting channel has a directional component along the circumferential direction Z.

[0055] As can be seen in Fig. 2b, the recess 27 is located in the region of position 33. In other words, the recess 27 is filled with coating material 5 or is located in the region of the reservoir 3, so that the opening cross-section is covered with coating material 5. Any air contained in the coating material 5 located in the recess 27 cannot therefore escape from the recess 27 through the opening cross-section of the recess 27.

[0056] However, the recess 29, as well as the connecting channel 35 and their respective opening cross-sections, are open to the environment and not covered by the doctor blade chamber 3 or the coating material 5. This allows the air trapped in the recess 27 to escape through the connecting channel 35 and the recess 29.

[0057] This allows the pumping effect to be suppressed or at least reduced compared to conventional screening methods. This enables higher processing speeds and throughput rates to be achieved without any loss of quality.

[0058] Figures 3a and 3b show another, alternative embodiment of an anilox roller 11'. Those elements of the anilox roller 11' that correspond to those of the anilox roller 11 bear the same reference numerals, but with a single stroke.

[0059] The anilox roller 11' differs from the anilox roller 11 in particular in that an alternative shape for the opening cross-section of the recesses 25', 27', 29' is implemented. The opening cross-sections are rectangular or square, as can be seen in Fig. 3b, which shows a detailed view of the anilox roller 11' of Fig. 3a in section B. This makes it possible to adapt the recess to the respective coating material 5, in particular its properties such as viscosity, flowability, and the like, especially to further reduce the pumping effect and / or to enable higher throughput rates without a pumping effect, or at least without increasing the pumping effect.

[0060] The connecting channels 35, 35' are dimensioned so that air inclusions from the recesses 27, 27' can escape through the connecting channels 35, 35' and / or the recesses 29, 29', but the coating material 5, 5' remains in the recess 27, 27'.

[0061] The inventors have further recognized that an alternative or additional measure to reduce the pumping effect consists in producing the rasterization in the anilox roller, in particular the rasterizations 23, 23' in the anilox rollers 11, 11' by means of laser etching engraving.

[0062] Figures 4a to 4c illustrate the steps involved in producing such a depression. In a first step, the surface 21 of the anilox roller 11 is coated with a masking coating 37, in particular over the entire surface. In the present example, the anilox roller 11 comprises a copper material.

[0063] As shown in Figure 4b, the masking coating 37 is partially removed by means of a laser 39, for example an Nd:YAG laser. This is done at the locations where the respective recesses are to be created.

[0064] In a subsequent etching step, as shown in Figure 4c, etching is carried out on the areas freed from the masking coating 37. FeC13, for example, can be used for this purpose. This is converted to FeC12 and CuC12 on the copper surface of the anilox roller 11, thereby removing copper and creating the depression 27.

[0065] In a subsequent step, the remaining masking coating 37 is removed, but without any further removal of the surface 21 of the anilox roller 11.

[0066] The features described or disclosed in the foregoing description, the claims and the figures can be essential for the invention in its various embodiments, both individually and in any combination.

[0067] REFERENCE MARK LIST

[0068] 1 printed work

[0069] reservoir

[0070] 5 Coating material

[0071] Carrier material

[0072] 9 squeegee blades

[0073] 11, 11 ' Anilox roller

[0074] 13, 13' axis of rotation

[0075] 15 Transfer roller

[0076] 17 Pressure roller

[0077] 19, 19' Lager

[0078] 21, 21' surface

[0079] 23, 23 ' grid

[0080] 25, 25' Deepening

[0081] 27, 27' Deepening

[0082] 29, 29' Deepening

[0083] 31, 31 ' Bridge

[0084] 33, 33' Position

[0085] 35, 35' connection channel

[0086] 37 Masking coating

[0087] 39 lasers

[0088] A, B section

[0089] L, L' Longitudinal direction

[0090] Z, Z' circumferential direction

Claims

REQUIREMENTS 1. Anilox roller (11, 11'), wherein at least one fluid coating material (5) can be applied from at least one reservoir (3) to the anilox roller (11, 11') and the coating material (5) can be transferred from the anilox roller (11, 11') to at least one receiving element (15, 7), wherein the surface (21, 21') of the lateral surface of the anilox roller (11, 11') has a plurality of recesses (25, 25', 27, 27', 29, 29') for at least temporarily receiving the coating material (5), characterized in that at least two recesses (27, 27', 29, 29') are fluidally connected by means of at least one connecting channel (25, 25') formed in the surface (21, 21') and / or below the surface (21, 21') and / or the lateral surface.

2. Anilox roller according to claim 1, characterized in that the coating material (5) comprises at least a high-viscosity battery material, at least a slurry coating material, at least a suspension, at least one, in particular chemical, active material, preferably of a battery, and / or at least a high-viscosity coating material, preferably for coatings in the HFC range.

3. Anilox roller according to claim 1 or 2, characterized in that the reservoir comprises at least one doctor blade and / or at least one chambered doctor blade (3).

4. Anilox roller according to one of the preceding claims, characterized in that the receiving element comprises at least one further roller (15) and / or at least one carrier material (7).

5. Anilox roller according to claim 4, characterized in that the carrier material (7) comprises at least a windable material, at least a flexible material, at least a film, at least a component of an electrical storage device, and / or at least a carrier material usable in a component of an electrical storage device, wherein the electrical storage device optionally comprises and / or forms at least a battery, an accumulator, a capacitor, an electrolyzer, a wet cell, a flow battery and / or a redox flow battery.

6. Anilox roller according to one of the preceding claims, characterized in that at least one depression (25, 25', 27, 27', 29, 29') comprises at least one cup, at least one slug, at least one pyramidal depression, at least one trough-shaped depression, at least one dome-shaped depression and / or at least one truncated pyramidal depression and / or the depression (25, 25', 27, 27', 29, 29') has at least partially a rectangular, square, pentagonal, triangular, hexagonal, circular, octahedral, and / or elongated cross-section, in particular opening cross-section and / or bottom cross-section, and / or several depressions form at least partially a uniform and / or geometric pattern, such as a "Penrose" grid.

7. Anilox roller according to one of the preceding claims, characterized in that the anilox roller (11, 11') is rotatable at least about an axis of rotation (13, 13'), wherein the recesses (27, 27', 29, 29') connected by the connecting channel (35, 35') are arranged at least partially offset about the axis of rotation (13, 13') and / or the connecting channel (35, 35') has at least one directional component in the circular direction and / or circumferential direction (Z) of the axis of rotation (13, 13').

8. Anilox roller according to one of the preceding claims, characterized in that the depression (25, 25', 27, 27', 29, 29') is produced by laser etching and / or direct laser ablation.

9. Printing unit (1) comprising at least one anilox roller (11, 11') according to any one of the preceding claims.

10. Printing unit according to claim 9, characterized in that the printing unit (1) comprises at least one reservoir (3) for at least one fluid coating material (5), wherein optionally the reservoir (3) is at least indirectly connected to the anilox roller (11, 11') for the transfer of the coating material (5) to the anilox roller (11, 11').

11. Printed matter according to claim 9 or 10, characterized by at least one further roller (15, 17) in operative connection with the anilox roller (11, 11'), wherein the anilox roller (11, 11') and the further roller (15) preferably roll against each other.

12. Printing unit according to claim 11, characterized in that at least one carrier material (7) which can be coated and / or is to be coated with the coating material (5) can be supplied to the anilox roller and / or the further roller (15).

13. Method for manufacturing an anilox roller (11, 11'), in particular according to one of claims 1 to 8, wherein the method comprises Provision of a roller (11, 11') with a cylindrical surface (21, 21') and formation of a grid (23, 23') of depressions (25, 25', 27, 27', 29, 29') on the surface (21, 21') of the roller (11, 11'), wherein the formation of the grid (23, 23') (i) comprising the formation of at least two depressions (27, 27', 29, 29') which are connected to each other by at least one connecting channel (35, 35') and / or (ii) includes forming the depressions (25, 25', 27, 27', 29, 29') by laser etching and / or direct laser ablation.

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