Length cutting doctor blade band for printing technique

Abstract

To provide a doctor blade band (100, 100') for cutting a doctor blade (200.1, 200.2, 200.3) for printing technique, particularly, gravure printing, flexographic printing and / or screen printing.SOLUTION: A doctor blade band includes a flat elongated base body (101; 301; 401) having a working blade area (102) formed in a longer direction. A doctor blade band (100) has continuous prescribed breaking points (110.1, 110.2, 110.3; 310; 410) continuing in a cross direction with respect to a longer direction (L) and at prescribed intervals (A) along the longer direction (L).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a doctor blade band for cutting to length individual doctor blades for the printing techniques, in particular doctor blades for gravure printing, flexography and / or screen printing. Furthermore, the present invention relates to a method for producing such a doctor blade band. [Background technology]

[0002] Doctor blades are used in printing technology to scrape excess printing ink from the surfaces of printing cylinders and printing rollers. Such doctor blades are usually based on a steel substrate with a specially shaped working edge.

[0003] In gravure and flexographic printing, in particular, the quality of the doctor blade has a decisive influence on the printing result. An uneven or irregular working edge of the doctor blade, which is in direct contact with the printing cylinder, can lead to incomplete wiping of the printing ink from the web of the printing cylinder. This can result in uncontrolled release of the printing ink onto the printing substrate. Therefore, doctor blades for printing techniques must be manufactured with great precision and adapted to the specific requirements of the printing technique.

[0004] Doctor blades are constantly worn during operation and must be replaced after a certain period of use. Therefore, doctor blades are often supplied as semi-finished products in the form of rolled-up doctor blade bands or so-called endless bands. When a new doctor blade is needed, it can be cut to the required length from the doctor blade band and installed on the printing press.

[0005] To facilitate cutting to length when replacing doctor blades and simplify the process for end users, it is known to pre-cut individual doctor blades to the required length, then reconnect them to each other at their face ends with strips of adhesive tape and roll them up to form a doctor blade band. Individual doctor blades can then be relatively easily separated from the doctor blade band by removing the adhesive tape strip from the subsequent doctor blade as needed. This eliminates the need for the end user to cut or trim the doctor blade band to the correct length.

[0006] However, in terms of manufacturing, this is a relatively expensive solution due to the additional process steps involved.

[0007] Therefore, there remains a need for an improved solution that does not have the above-mentioned drawbacks. Summary of the Invention

[0008] It is therefore an object of the present invention to provide an improved solution for replacing worn doctor blades in printing technology. In particular, a doctor blade band for cutting doctor blades to length for printing technology should be provided that can be manufactured as efficiently as possible and allows individual doctor blades to be cut to length or easily separated. In particular, this is done in such a way that the quality of the doctor blade is not compromised during cutting and the safety of the end user is guaranteed.

[0009] This object is solved by a doctor blade band according to claim 1 and a method for producing a doctor blade band according to claim 14.

[0010] Thus, according to a first aspect, the present invention relates to a doctor blade band for cutting to length individual doctor blades for printing techniques, in particular doctor blades for gravure printing, flexography and / or screen printing, characterized in that the doctor blade band comprises a flat, elongate substrate having a working cutting edge area formed in the longitudinal direction, and the doctor blade band has a series of predetermined breaking points extending transversely to the longitudinal direction and at predetermined intervals along the longitudinal direction.

[0011] The doctor blade band or the individual doctor blades obtained therefrom are designed to doctor printing ink from the printing cylinder, the anilox roller and / or the inking roller.

[0012] As shown, the predetermined break points introduced in accordance with the present invention allow individual doctor blades to be separated or severed by simply buckling, creating a clearly defined break edge. The properties and quality of the individual doctor blades are not compromised during cutting to length. In particular, the doctor blades are not deformed or damaged, especially in the critical working edge area. Furthermore, the break edge is such that there is no significant risk of injury to the end user.

[0013] This is in contrast to experimentally produced doctor blade bands that had only a few spaced perforations instead of a continuous, predetermined break point. In this case, poorly defined break edges were produced during cutting to length due to buckling, which also had sharp edges. Therefore, there is a significant risk of damage from such doctor blades, and the quality of the individual doctor blades may be compromised during cutting to length.

[0014] Doctor blades for printing technology are relatively thin compared to other blades. Typically, doctor blades for printing technology have a thickness of less than 0.4 mm. Furthermore, doctor blades for printing technology must be manufactured with specific precision because they come into direct contact with the printing cylinder or roller.

[0015] In particular, the doctor blade band has a thickness of 0.05 to 0.35 mm, especially 0.15 to 0.3 mm. This makes the doctor blade suitable for typical applications. At the same time, such a thickness allows a well-defined, predetermined breaking point to be introduced into the doctor blade band, made of materials typically used for doctor blades in the printing industry, in a reliable and efficient manner, allowing it to be bent and cut to length by hand.

[0016] The distance between the predetermined breaking points is in particular 10 cm to 5 m, in particular 20 cm to 2 m, although other distances are also possible.

[0017] The cross-sectional area of ​​the doctor blade band may be rectangular, or the cross-sectional area may have a shape that deviates from rectangular, the latter being the case, for example, when the doctor blade band is ground for structuring purposes.

[0018] In particular, the working edge of the doctor blade band has a ground finish. Preferably, the working edge is tapered in one or more stages toward the free end, chamfered in a tapered wedge shape, chamfered, and / or rounded. Different ground finishes can also be combined with each other. For example, the working edge can be tapered in one or more stages toward the free end and simultaneously beveled at the free end.

[0019] Thus, the doctor blade band may be, for example, a lamellar doctor blade band, a wedge-grind doctor blade band, a chamfered doctor blade band and / or a rounded doctor blade band.

[0020] In this context, the term "predetermined break point" refers to an area of ​​the doctor blade band that will predictably fail under load due to its structure, shape and / or material properties.

[0021] The expression "transverse to the longitudinal direction" means in this case that the predetermined breaking point extends in a direction approximately perpendicular to the longitudinal direction of the doctor blade band, in particular at an angle of 80 to 90°, preferably 90°.

[0022] The predetermined breaking point is continuous, which in particular means that it extends without interruption across the entire width of the doctor blade band. Preferably, the predetermined breaking point extends in a straight line.

[0023] The length of the doctor blade band in this case corresponds, as usual, in particular to the dimension of the doctor blade band measured along the direction of its longest extension. The width of the doctor blade band, as usual, in particular to the dimension of the doctor blade band perpendicular to the length extending from the rear edge of the doctor blade opposite the working edge of the doctor blade to the working edge. The thickness of the doctor blade band, as usual, in particular to the extent of the doctor blade band perpendicular to the length and width extending from the upper side to its lower side. In particular, the upper and lower sides form the two largest surfaces of the doctor blade band.

[0024] Typically, the length of the doctor blade band is greater than the width of the doctor blade band, which in turn is greater than the thickness of the doctor blade band.

[0025] For example, the thickness of the doctor blade band is 0.03 to 1 mm, preferably 0.1 to 0.6 mm. The width of the doctor blade band is particularly 5 to 100 mm, preferably 8 to 80 mm. The length of the doctor blade band is, for example, 1 to 150 m, preferably 25 to 100 m.

[0026] Particularly preferably, the doctor blade band does not have perforations in the area of ​​the predetermined break point, which prevents the formation of rough or undefined break edges. However, in special applications, it is also possible to provide one or more perforations in the area of ​​the predetermined break point.

[0027] Preferably, the predetermined breaking point extends across the entire width of the doctor blade band so that the doctor blade band is substantially uniformly weakened to breaking behavior across the entire width of the doctor blade band.

[0028] According to certain embodiments, the material of the doctor blade band at the predetermined break point has at least a partially different grain structure and / or microstructure than the region of the doctor blade band adjacent to the predetermined break point in the longitudinal direction. This is particularly true over the entire length of the predetermined break point. The length of the predetermined break point is measured in the width direction of the doctor blade band. In particular, the predetermined break point is made of the same material as the region of the doctor blade band adjacent to the predetermined break point in the longitudinal direction and / or other regions of the doctor blade band.

[0029] In particular, the material of the doctor blade band at the predetermined breaking point has at least partially higher hardness and / or brittleness than the region of the doctor blade band adjacent to the predetermined breaking point in the longitudinal direction, and this is particularly true over the entire length of the predetermined breaking point, and in particular, the predetermined breaking point is made of the same material as the region of the doctor blade band adjacent to the predetermined breaking point in the longitudinal direction and / or the other regions of the doctor blade band.

[0030] The term "hardness" is used herein to refer to Vickers hardness measured in accordance with standard DIN EN ISO 6507-1:2018~-4:2018.

[0031] In particular, regions of a predetermined break point having a different grain structure and / or microstructure and / or regions of a predetermined break point having higher hardness and / or brittleness extend through the thickness of the doctor blade band over the entire thickness of the predetermined break point, although it is also possible for these regions to extend through only part of the thickness.

[0032] In particular, the width of the predetermined breaking point measured in the longitudinal direction of the doctor blade band is between 25 and 800 μm, in particular between 100 and 500 μm.

[0033] In particular, the predetermined break points each have or consist of a heat-affected zone, which can be formed by suitable conditions when introducing the predetermined break points into the doctor blade body, for example by suitable selection of process parameters during laser processing.

[0034] In a preferred embodiment, the doctor blade band has a substantially constant material thickness in the region of the predetermined break point along the entire width of the doctor blade band. In other words, in this case, the material thickness at the predetermined break point is essentially constant or the same thickness. This means that particularly clean break edges can be obtained when cutting to length.

[0035] In principle, however, it is also possible to provide a material thickness that varies along the width of the doctor blade band in the region of the predetermined breaking point, if this is expedient.

[0036] The thickness or material thickness at the predetermined breaking point can be essentially the same as the thickness or material thickness of the doctor blade band in the region adjacent to the predetermined breaking point in the longitudinal direction, in which case the breaking behavior at the predetermined breaking point can be controlled, for example, by the material properties at the predetermined breaking point.

[0037] Particularly preferably, the predetermined breaking point has a continuous groove extending transversely to the longitudinal direction, so that in the region of the groove the doctor blade band is tapered and therefore weakened.

[0038] The grooves are continuous, which means that they extend over the entire width of the doctor blade band and are in particular open at both end faces. Preferably, the grooves extend in a straight line.

[0039] In particular, the grooves can have a constant cross-sectional area across the width of the doctor blade band. However, in principle, variable cross-sectional areas are also possible. The latter can be advantageous, for example, in the case of specially shaped doctor blade bands, such as lamellar doctor blades, since this allows the material thickness in the area of ​​the predetermined breaking point to remain constant.

[0040] Particularly preferably, the doctor blade band does not have perforations in the region of the grooves, which reduces or prevents the formation of rough or undefined breaking edges.

[0041] However, in special applications it is also possible to provide one or more perforations in the region of the groove.

[0042] In a preferred embodiment, the grooves decrease in width as they increase in depth, the width of the grooves being measured in the longitudinal direction of the doctor blade band, thus providing clearly defined break edges when cutting to length by buckling.

[0043] In particular, the grooves have a U-shaped or V-shaped cross section, which has been found to be the optimal shape.

[0044] However, grooves having other cross-sectional areas are also possible, for example rectangular cross-sectional areas.

[0045] Particularly preferably, the grooves have a depth of 20 to 80%, especially 35 to 65%, of the thickness of the doctor blade band, which provides good buckling properties and clean breaking edges in most materials used for doctor blades in printing technology.

[0046] In particular, the grooves have a depth of 20 to 150 μm, in particular 25 to 90 μm. This is particularly true when the doctor blade has a steel substrate.

[0047] Particularly preferably, the grooves in their widest area have a width, measured in the longitudinal direction of the doctor blade band, of 20 μm to 500 μm, in particular 50 μm to 200 μm. This is particularly true when the doctor blade has a steel substrate.

[0048] In particular, the doctor blade band has a different grain structure and / or microstructure in the blade region adjacent the groove surface than an inner region of the doctor blade band located further inwardly of the substrate, and in particular both the blade region and the inner region are made of the same material.

[0049] In particular, the cutting edge region is a heat-affected region, which can be formed by suitable conditions when introducing grooves into the doctor blade body, for example by suitable selection of process parameters during laser machining.

[0050] According to a further advantageous embodiment, the doctor blade band has a higher hardness and / or brittleness in the blade region adjacent to the groove surface than in an inner region of the doctor blade band located further inside the substrate, in particular both the blade region and the inner region being made of the same material.

[0051] The blade region preferably has a thickness of 5 to 60%, in particular 20 to 50%, of the depth of each groove.

[0052] In particular, the blade region has a thickness of 1 to 50 μm, in particular 5 to 30 μm, this being particularly the case when the doctor blade has a steel substrate.

[0053] Special blade areas can be used to specifically improve the breaking behavior at a given breaking point, resulting in better defined or cleaner breaking edges.

[0054] The blade area can be characterized, for example, by preparing a polished section that is polished to a high gloss and examined under a reflected light microscope. Corresponding methods are known to those skilled in the art.

[0055] In a further embodiment, the predetermined breaking point, in particular the groove, has a protrusion, in particular a rib-like protrusion, that projects beyond the surface of the doctor blade band, which allows for tactile location of the predetermined breaking point and simplifies cutting to length.

[0056] In particular, the protrusions are located at predetermined break points, in particular at the transition between the grooves and the adjacent areas of the doctor blade band.

[0057] In particular, on either side of the predetermined breaking point, in particular the groove, there are longitudinal rib-like projections extending along the entire width of the doctor blade body.

[0058] According to a further advantageous embodiment, there are protrusions, in particular rib-like protrusions, both on the underside of the doctor blade band and on the upper side of the doctor blade band.

[0059] The substrate of the doctor blade band is made in particular of metal, plastic and / or composite material, in particular steel, thermoplastic material, thermosetting material and / or fiber-reinforced plastic.

[0060] Particularly preferably, the substrate comprises or consists of a metal, in particular steel, which may be, for example, carbon steel or stainless steel.

[0061] According to a further advantageous embodiment, the doctor blade band has one or more coatings at least in the region of the working edge, which in particular consist of a material different from that of the substrate, in particular having a different chemical composition from that of the substrate.

[0062] For example, one or more coatings may be wear-reducing and / or friction-reducing coatings. For example, the coating may be a metallic coating, a hard material coating, a ceramic coating, or a polymer coating. Such coatings may be used to further customize the doctor blade for a particular application.

[0063] Preferably, the predetermined break point, in particular the groove, is a predetermined break point created by laser machining, whereby machining is performed by a laser light beam directed at the area to be machined on the doctor blade band, whereby interaction of the laser light with the material of the doctor blade band causes local material modification and / or material removal or ablation, respectively.

[0064] Laser machining has proven to be a particularly advantageous method: on the one hand, predetermined breaks, especially grooves, can be introduced by laser machining in a particularly efficient manner with different dimensions, shapes and / or cross-sectional profiles. On the other hand, laser machining has the advantage that, by appropriate selection of the process parameters, grooves with the special cutting areas described above can be directly produced.

[0065] Because the doctor blade band is processed purely by the laser light during laser processing and therefore does not interact with physical tools (e.g., in milling) or materials (e.g., in etching), the risk of contamination of the doctor blade band with wear material from the tool or material is also prevented. This is important in the case of doctor blades for printing technology, since even slight contamination in the area of ​​the working edge can lead to significant losses in quality.

[0066] Further details on how to carry out the laser processing can be found later in connection with the method according to the invention.

[0067] The doctor blade bands are preferably in the form of a roll, particularly in a container with an opening for removing the doctor blade bands, which allows for space-saving transport and storage of the doctor blade bands. When a container is used, the doctor blade bands can also be protected from damage and contamination, and can be easily removed and cut to length through the opening.

[0068] A second aspect of the present invention relates to a method for manufacturing a doctor blade band for cutting individual doctor blades to length for printing technology, in which the doctor blade band to be processed is provided and a series of predetermined breaking points, in particular continuous grooves extending transversely to the longitudinal direction, are introduced into the band at predetermined intervals along the longitudinal direction.

[0069] The doctor blade band to be processed preferably has a substrate made of metal, plastic and / or composite material, in particular steel, thermoplastic material, thermosetting material and / or fiber-reinforced plastic, with steel, e.g., carbon steel or stainless steel, being particularly preferred.

[0070] In particular, this process is carried out so that the doctor blade band is as described above, and preferably optionally has one or more of the features described above.

[0071] According to a particularly preferred embodiment, the doctor blade band is moved continuously in the longitudinal direction, preferably at a constant speed, during the insertion of the predetermined breaking point, in particular the groove. The speed is in particular between 1 and 100 m / min, preferably between 10 and 50 m / min. This allows a very efficient processing of the doctor blade band.

[0072] In this case, the tool used to introduce the predetermined break point can move along the longitudinal direction in the cross section during processing, thereby allowing a laterally extending predetermined break point, in particular a groove, to be introduced into the doctor blade band despite the movement of the doctor blade band.

[0073] According to a particularly preferred embodiment, the predetermined break points, in particular the grooves, are introduced by laser machining with a laser light beam, the advantages of which have already been mentioned above in connection with the doctor blade band according to the invention.

[0074] In particular, the laser light can be continuous or pulsed. A continuous laser light beam, also called "continuous wave laser light," consists of a light wave with a constant intensity over time. A pulsed light laser beam has a pulsating intensity of the light wave. Corresponding laser processing systems are known per se to those skilled in the art.

[0075] The movement of the laser beam can be achieved in laser processing by X deflection units for deflecting and focusing the laser beam in one dimension, or by XY deflection units for deflecting and focusing the laser beam in two dimensions. For example, so-called galvanometer scanners with mirrors are suitable.

[0076] The power of the laser light beam during laser processing is preferably 5 to 100 W, in particular 30 to 70 W. This allows for good processing of materials typically used for doctor blades, such as steel. However, for other materials or special doctor blades, lower or higher powers may also be appropriate.

[0077] Particularly preferably, the laser light is UV light, visible light, or infrared light.For example, the wavelength of the light is in the range of 150 nm to 3 μm, preferably 400 nm to 2.5 μm, and more specifically 500 nm to 1.5 μm.

[0078] The focal diameter of the laser beam at the point of impact with the doctor blade is advantageously 1 to 100 μm, in particular 30 to 70 μm, which also makes it possible to form relatively fine, predetermined breaks, in particular grooves.

[0079] Preferably, the doctor blade band is moved continuously in the longitudinal direction during the insertion of the predetermined break point, in particular at a constant speed, and at the same time the focus of the laser light beam on the doctor blade band is moved both in the longitudinal direction and perpendicularly thereto during processing, which makes it possible to achieve a very high throughput, since the laser light beam can be moved very quickly and precisely by a corresponding deflection unit.

[0080] During laser machining, the process parameters, particularly the power and movement of the laser light beam, are controlled to, among other things, modify material properties and / or achieve material removal results.

[0081] In particular, the material properties change, resulting in changes in grain structure, microstructure, hardness and / or brittleness.

[0082] In particular, grooves are formed as a result of material removal.

[0083] According to a particularly advantageous embodiment, the process parameters during laser machining, in particular the power and movement of the laser light beam, are controlled in such a way that both grooves are formed while at the same time the grain structure, microstructure, hardness and / or brittleness of the doctor blade band are changed in the groove edge region.

[0084] According to an advantageous embodiment, process parameters are controlled during laser machining such that deformation of the doctor blade is reduced or prevented.

[0085] Preferably, the process is controlled by a control unit, in particular the control unit controls the movement of the laser light beam, the movement of the doctor blade band and / or the power of the laser light beam.

[0086] In particular, the doctor blade band is rolled up after the grooves are formed and preferably packaged in a container.

[0087] Further advantageous embodiments and feature combinations of the invention emerge from the following detailed description and the claims as a whole.

[0088] The drawings used to explain the embodiments show: [Brief explanation of the drawings]

[0089] [Figure 1] FIG. 1 shows an apparatus for continuously laser processing a doctor blade band from the side. [Figure 2] 2 is a schematic top view of a band portion having a V-shaped continuous groove processed by the apparatus of FIG. 1. FIG. [Figure 3] 3 is a schematic side view of the processed band portion of FIG. 2. FIG. [Figure 4] 4A and 4B show the guidance of a laser light beam during the insertion of grooves into the movable doctor blade band from FIGS. 2 and 3. FIG. [Figure 5] On the left, the completed doctor blade band in wound form in a doctor blade box with a slit-like removal opening, and on the right, a schematic diagram showing the cutting of individual doctor blades from the doctor blade band. [Figure 6] FIG. 1 shows a photomicrograph of a steel doctor blade band in the region of a U-shaped groove created by laser machining. [Figure 7] FIG. 1 shows a photomicrograph of a steel doctor blade band in the area of ​​a predetermined break point introduced by laser processing in the form of a continuous heat-affected zone with altered grain structure and microstructure. DETAILED DESCRIPTION OF THE INVENTION

[0090] As a general rule, the same parts in the drawings are given the same reference numerals.

[0091] Figure 1 shows a side view of an apparatus 10 for laser machining of a doctor blade band 100. Figures 2 and 3 show a machined band portion 100c in top and side views.

[0092] In FIG. 1, on the left side, there is a take-up band portion 100a of the doctor blade band on a first spool 11a. The doctor blade band 100 is continuously unwound from the spool 11a, passes through a band centering device 12, passes through a laser processing station 14, and is guided through a band supplying device 13 to a second spool 11b. The doctor blade band 100 has a base body 101 and a step-tapered working blade 102 extending in the longitudinal direction L (see FIG. 2). For example, the doctor blade band is a lamellar-shaped doctor blade band having a length of 50 mm and a width of 50 mm, and is made of steel having a thickness of 0.15 mm.

[0093] Between the coil 11a and the laser processing station 14 is an unwound, unprocessed band portion 100b, which enters the laser processing station 14 and is provided with a laser light beam 15 at regular intervals, with predetermined break points running transversely to the longitudinal direction of the doctor blade band 100 in the form of continuous grooves 110.1, 110.2, and 110.3 (see FIGS. 2 and 3). The laser processing system 14 includes a laser source 14.1, e.g., a fiber laser, with a downstream galvanometer scanner 14.2 that can spatially move the laser beam. During processing, the doctor blade band moves continuously past the laser processing station 14 at a constant speed, e.g., 30 m / min. A control unit ensures that the laser light beam 15 is moved over the doctor blade band 100 by the laser meter scanner 14.2 so that the transverse grooves are formed. The wavelength of the laser light 15 is, e.g., 1064 nm.

[0094] After the doctor blade band 100 has passed the laser processing station 14, the processed band portion 100c advances to a second reel 11b where there is a previously processed and wound band portion 100d.

[0095] 2 shows a top view of the processed band portion 100c of the doctor blade band 100. Perpendicular to the longitudinal direction L of the doctor blade band 100c, three consecutive V-shaped grooves 110.1, 110.2, 110.3 with a constant groove cross-section extend parallel to the transverse direction B (= width direction). The grooves extend linearly across the entire width of the doctor blade band 100, and the distance A between the grooves is, for example, 50 cm. The V-shaped grooves 110.1, 110.2, 110.3 form predetermined breaking points at which the doctor blade band can be cut to length.

[0096] 3 shows a top view of the processed band portion 100c of the doctor blade band 100 as seen from the side, where the width NB of the V-shaped groove (measured along the longitudinal direction L) is, for example, 250 μm, and the depth NT (measured along the thickness direction D) is, for example, 50 μm.

[0097] Figure 4 shows the situation after two grooves 110.1 and 110.2 have been inserted, just before the third V-shaped groove 110.3 is inserted. While the laser processing device 14 remains in place, the doctor blade band moves at a constant speed (to the right in Figure 4), so that the focus of the laser light is directed in an oblique direction 15.1 across the doctor blade band. This allows grooves extending perpendicular to the longitudinal direction to be introduced, even as the doctor blade band passes. Therefore, during the processing operation, the laser light beam 15 is moved both parallel to the longitudinal direction and perpendicular to it.

[0098] FIG. 5 shows, on the left, a fully completed doctor blade band 100' having grooves extending at regular intervals along its entire length perpendicular to its longitudinal direction, in a wound form in a doctor blade box 20 or container, respectively.

[0099] The doctor blade band 100' can be removed from the doctor blade box 21 through the slit-like opening 21.

[0100] Figure 5 shows, on the right, a situation where two individual doctor blades 200.1, 200.2 have already been cut to length or separated from the doctor blade band 100', and a third individual doctor blade 200.3 has just been separated by buckling the groove 110.3.

[0101] The individual doctor blades thus obtained can then be used in a printing press to strip off printing ink, for example in gravure or flexographic printing.

[0102] Figure 6 shows a micrograph of the steel doctor blade band in the region of the U-shaped groove 310 created by laser machining. The steel doctor blade band has a steel substrate 301 with a thickness 303 of 0.15 mm. The longitudinal direction L is along the left-right direction in Figure 6.

[0103] The groove 310 is approximately 52 μm deep and approximately 100 μm wide at its top (measured longitudinally). The blade region 312 (shown brightly in FIG. 6) adjacent to the groove surface 311 is a heat-affected zone created by the laser machining that has a different grain structure and microstructure compared to the more interior regions of the substrate 301. The blade region 312 has a thickness of approximately 15-30 μm.

[0104] On either side of the groove 310 there are also rib-like protrusions 313a, 313b that extend along the entire width of the doctor body (the width direction is along the image plane direction in Figure 6). The protrusions 313a, 313b are created directly during laser machining.

[0105] FIG. 7 shows a photomicrograph of a steel doctor blade band in the region of a predetermined break point 410 introduced by laser machining. The steel doctor blade band has a steel substrate 401 with a thickness of approximately 0.20 mm. In FIG. 7, the longitudinal direction is also horizontal. The predetermined break point 410 is designed as a heat-affected zone with a modified microstructure compared to the longitudinally adjacent regions (light areas). In the region of the upper and lower predetermined break points, rib-like protrusions 413a, 413b are formed and extend across the entire width of the doctor blade band.

[0106] The above-described methods and doctor blades should be understood as illustrative examples only and can be modified within the scope of the present invention.

[0107] For example, it is possible to use doctor blade bands of different shapes, for example with rounded or chamfered working edges, and / or to provide doctor blade bands made of different materials, for example plastic.

[0108] In principle, during the processing of the doctor blade band 100, it is also possible to stop the band at each point to be processed, insert the respective groove, and then move the doctor blade band further. In this case, the laser processing system can be simplified, since only one spatial deflection of the laser light 15 is required to insert the grooves.

[0109] Additionally, several doctor blade bands can be run parallel and adjacent to each other and processed in the same laser processing system, which can increase throughput.

[0110] The cross-sectional shapes of the grooves 110.1, 110.2, 110.3 can in principle also be chosen to be different, for example rectangular or asymmetrical. Likewise, the dimensions of the grooves can be adapted to special materials as required.

[0111] The predetermined breaking point 410 in the doctor blade of Figure 7 can be produced without the rib-like projections 413a, 413b if the process parameters are selected accordingly. The same is true for the doctor blade shown in Figure 6.

[0112] In summary, it can be said that a new and highly efficient solution has been found for the supply of cut-to-length doctor blade bands. The doctor blade bands thus produced and the individual doctor blades which can be cut to length therefrom are of high quality and are perfectly suitable, in particular, for doctoring printing inks in printing technology.

Claims

1. 1. A doctor blade band (100, 100') for cutting individual doctor blades (200.1, 200.2, 200.3) for the printing technology, in particular doctor blades for gravure printing, flexography and / or screen printing, characterized in that the doctor blade band (100) comprises a flat, elongated base body (101; 301; 401) with a working cutting area (102) formed in the longitudinal direction, and in that the doctor blade band (100) has successive predetermined breaking points (110.1, 110.2, 110.3; 310; 410) extending transversely to the longitudinal direction (L) and spaced apart at predetermined intervals (A) along the longitudinal direction (L).

2. 2. The doctor blade band of claim 1, wherein the predetermined breaking points (110.1, 110.2, 110.3; 310; 410) extend across the entire width (B) of the doctor blade band such that the doctor blade band (100) is substantially uniformly weakened to breaking behavior across the entire width (B) of the doctor blade band.

3. 3. Doctor blade band according to claim 1 or 2, characterized in that the doctor blade band (100) does not have perforations in the area of ​​the predetermined breaking points (110.1, 110.2, 110.3; 310; 410).

4. 4. A doctor blade band according to claim 1, wherein the material of the doctor blade band at the predetermined breaking point (310; 410) has in each case at least partially different grain structure, microstructure, hardness and / or brittleness than the region of the doctor blade band adjacent to the predetermined breaking point in the longitudinal direction.

5. 5. Doctor blade band according to at least one of claims 1 to 4, wherein said predetermined breaking points comprise continuous grooves (110.1, 110.2, 110.3; 310) extending transversely to said longitudinal direction (L).

6. 6. Doctor blade band according to claim 5, wherein said grooves (110.1, 110.2, 110.3; 310) narrow in width with increasing depth.

7. Doctor blade band according to claim 5 or 6, wherein the grooves (110.1, 110.2, 110.3; 310) have a depth of 20 to 80%, in particular 35 to 65%, of the thickness (D) of the doctor blade band.

8. 8. Doctor blade band according to at least one of claims 5 to 7, wherein the doctor blade band in the cutting area (312) adjacent to the surface (311) of the groove (110.1, 110.2, 110.3; 310) has in each case a different grain structure, microstructure, hardness and / or brittleness than an inner area of ​​the doctor blade band which is further inside the substrate (301), in particular the cutting area (312) and the inner area also consisting of the same material.

9. Doctor blade band according to claim 8, wherein the cutting edge region (312) has a thickness of 1 to 50 μm, in particular 5 to 25 μm.

10. 10. Doctor blade band according to at least one of the preceding claims, wherein the predetermined breaking points (110.1, 110.2, 110.3; 310; 410), in particular the grooves, are produced by laser machining.

11. 11. Doctor blade band according to at least one of claims 1 to 10, wherein the doctor blade band (100) comprises a steel substrate (101; 301; 401), optionally with one or more coatings present at least in the working cutting edge region (102).

12. Doctor blade band according to at least one of claims 1 to 11, wherein the doctor blade band (100) has a thickness (D) of 0.05 to 0.35 mm, in particular 0.15 to 0.3 mm.

13. 13. Doctor blade band according to at least one of claims 1 to 12, wherein the doctor blade band is present as a roll, preferably in a container (20) having an opening (21) for removing the doctor blade band (100').

14. 14. A method for manufacturing a doctor blade band according to claim 1, characterized in that a doctor blade band (100, 100') to be processed is provided and that a series of predetermined breaking points (110.1, 110.2, 110.3; 310; 410), in particular a series of grooves extending transversely to the longitudinal direction (L), are introduced into the doctor blade band at predetermined intervals (A) along the longitudinal direction (L).

15. 15. The method according to claim 14, characterized in that the doctor blade band (100) moves continuously, in particular at a constant speed, in the longitudinal direction (L) during the insertion of the predetermined breaking points (110.1, 110.2, 110.3; 310; 410).

16. 16. Method according to claim 14 or 15, characterized in that the predetermined breaking points (110.1, 110.2, 110.3; 310; 410) are introduced by laser machining with a laser light beam (15).

17. 17. A method according to claim 16, characterized in that the focal point of the laser light beam (15) on the doctor blade band moves during processing both in the longitudinal direction and perpendicular thereto.

18. 18. A method according to claim 16 or 17, characterized in that the power of the laser light beam (15) is controlled so that (i) the grain structure and / or microstructure of the doctor blade band changes at the predetermined breaking point, (ii) an increase in hardness and / or brittleness occurs in the region of the predetermined breaking point, and / or (iii) material removal creates a continuous groove (110.1, 110.2, 110.3; 310) extending transversely to the longitudinal direction (L).

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