Rotary die cutter unit and assembly

Abstract

A rotary die cutter unit (20) is described. The rotary die cutter unit (20) comprises an anvil holding cylinder (32) and an anvil plate (34) mounted on the anvil holding cylinder (32), a tool holding cylinder (28) and a die plate (30) mounted on the tool holding cylinder (28). The die plate (30) is configured to cut a substrate (22) into blanks (36). The die plate (30) and / or the anvil plate (34) comprises stripping means (48) for stripping waste particles (40; 41) from the blanks (36). Further, an assembly comprising at least one printing unit and such a rotary die cutter unit (20) is described.

Description

[0001] Rotary Die Cutter Unit and Assembly

[0002] The invention relates to a rotary die cutter unit comprising an anvil holding cylinder and an anvil plate mounted on the anvil holding cylinder, a tool holding cylinder and a die plate mounted on the tool holding cylinder, wherein the die plate is configured to cut a substrate into blanks. Further, the invention relates to an assembly comprising at least one printing unit and such a rotary die cutter unit.

[0003] Rotary die cutter units are known. They can be used in combination with printing units in an inline process to deliver multi-out and multi-up, flat, die-cut trays and boxes, along with wrap-arounds and large point of purchase / point of sale (POP / POS) displays.

[0004] Typically, one the cylinders (the upper one) carries a “male” plate, and the other cylinder (the lower one) carries a “female” plate. On the male plate, there can be the cutting lines (knives) and the creasing lines, and the female plate carries the anvil line for the cutting and the counter creasing lines (which consist of two parallel lines so that a creasing channel is formed. When changing from one job to another job (meaning: to a different blank), it is necessary to change both plates.

[0005] In order to reduce waste, blanks may be cut from the substrate by a single cut, i.e. blanks are arranged adjacent to each other without a gap in between. Due to the specific shape of the blanks, there usually are small insular sections of the substrate that are not connected to the matrix (the remainder of the substrate when the blanks are separated therefrom) and form waste particles which should not be delivered together with the blanks and thus have to be removed. In the prior art, there are dedicated stripping station with dedicated stripping tools for this task.

[0006] The object of the invention is to provide a rotary die cutter unit as well as an assembly with a rotary die cutter unit which are more efficient.

[0007] In order to achieve this object, the invention provides a rotary die cutter unit comprising an anvil holding cylinder and an anvil plate mounted on the anvil holding cylinder, a tool holding cylinder and a die plate mounted on the tool holding cylinder. The die plate is configured to cut a substrate into blanks. Further, the die plate and / or the anvil plate comprises stripping means for stripping waste particles from the blanks.

[0008] As the stripping means are part of the rotary die cutter, the rotary die cutter unit according to the invention combines the functionality of a rotary die cutter and a stripping station. Thus, no additional station for stripping of the waste particles is required. In this way, the cost and necessary space for an inline assembly comprising such a rotary die cutter unit can be significantly reduced. Further, as the stripping means are part of the die plate and / or the anvil plate, the stripping means can be arranged at the exact spot where they are most effective for stripping the waste particles. Thus, the stripping is highly accurate and reliable. Also, setup times are reduced as there is no need for a separate stripping unit to be synchronized with the rotary die cutter unit.

[0009] The waste particles can be isolated portions (“insular sections”) between two adjacent blanks, either in the form of an inevitable area between two adjacent blanks or in the form of a deliberately provided narrow strip between adjacent blanks, the narrow strip being the result of a double cut. A double cut is used if there is print on a first side of the cut and no print on the second side of the cut. To avoid white lines on the first side or thin printed lines on the second side, a double cut can be used for avoiding any issues in this regard. The waste particles can also be isolated portions (“windows”) within a blank.

[0010] The general aim is to have printed substrates for which a matrix between the blanks can be avoided, for many reasons. A matrix between blanks requires double cuts which in turn require more expensive tools with double cutting lines. Further, a matrix between blanks results in more waste of the expensive substrate material.

[0011] The stripping means serve for removing the waste particles irrespective of whether there is a matrix remaining between adjacent blanks or if the blanks are arranged such that there is not matrix. Any waste particles are held by the stripping means so that they are not delivered with the blanks. In one embodiment, the stripping means are stripping pins or stripping needles which are highly effective for stripping waste particles from the blanks.

[0012] In addition or in the alternative, stripping means may be a monolithic part of the die plate or the anvil plate, i.e. the stripping means are each formed in one piece with the die plate or the anvil plate. Thus, the position of the stripping means relative to the waste particles is fixed and can easily be designed for high reliability and efficiency with respect to stripping. Also, there is no assembly required for the stripping means which reduces the effort and guarantees high precision.

[0013] In a further embodiment, the die plate and / or the anvil plate comprises counter stripping means arranged complementarily to the stripping means so that each waste particle is located between a stripping means and a corresponding counter stripping means when the stripping means contacts the respective waste particle. In this way, the stripping effectiveness can be increased as the counter stripping means hold the particles in place when he stripping means contacts or pierces the respective waste particle.

[0014] The counter stripping means may be elastic to further improve the stripping effectiveness.

[0015] In one embodiment the counter stripping means comprise an elastomer which form an economic way to provide a highly effective elastic counter stripping means.

[0016] The maximum thickness of the die plate may be different from the maximum thickness of the anvil plate so that each plate can be individually designed for maximum effect.

[0017] In a further embodiment, the maximum thickness of the die plate is less than the maximum thickness of the anvil plate, in particular by at least 25%.

[0018] According to another aspect of the invention, the rotary die cutter unit comprises a stripping device for stripping the waste particles from the stripping means during operation. In this way, the waste particles are reliably removed from the stripping means during operation of the rotary die cutter unit so that the stripping means stay effective at stripping the waste particles. In order to achieve the object, the invention further provides an assembly comprising at least one printing unit and a rotary die cutter unit according to the invention with the above-mentioned advantages.

[0019] Any individual feature of any of the embodiments disclosed above may be part of any of the embodiments disclosed above thus forming a further embodiment of the invention. In other words, any or all of the individual features disclosed above can be combined in a further embodiment of the invention.

[0020] The foregoing aspects and many of the attendant advantages of the claimed subject matter will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:

[0021] - Figure 1 schematically shows an assembly according to the invention and a rotary die cutter unit according to the invention;

[0022] - Figure 2 schematically shows the rotary die cutter unit of Figure 1 in a sectional view;

[0023] - Figure 3 schematically shows an example of the cutting pattern of the rotary die cutter unit of Figure 1 ; and

[0024] - Figure 4 schematically shows a second example of the cutting pattern of the rotary die cutter unit of Figure 1.

[0025] Figure 1 shows an assembly 10 comprising printing units 12 and a rotary die cutter unit 20.

[0026] The rotary die cutter unit 20 is generally speaking provided for cutting printed blanks from a substrate. This will be explained in more detail below.

[0027] The rotary die cutter unit 20 is here operated downstream of the printing units 12. It however is also possible to operate the rotary die cutting unit 20 offline and to process therein a pre-printed web supplied as a roll.

[0028] The printing units 12 used in this example as part of the assembly 10 can be flexographic printing units, digital printing units, or web-offset printing units. The printing units 12 do not have to be from the same type; combinations from different printing units can be used, for example digital printing units with additional flexographic printing units can be used.

[0029] The printing units 12 are configured for printing on a substrate 22 that is conveyed in direction X, while the rotary die cutter unit 20 is configured to cut the substrate 22 after the printing process.

[0030] In an alternative embodiment, the assembly 10 can comprise any number of printing units 12, however at least one.

[0031] In an example, the assembly 10 can comprise one flexographic printing unit 12 for each color required to form the product.

[0032] The rotary die cutter unit 20 has a tool cylinder 24 and an anvil cylinder 26.

[0033] The tool cylinder 24 comprises a tool holding cylinder 28 (see Figure 2) and a die plate 30 mounted on the tool holding cylinder 28.

[0034] The anvil cylinder 26 comprises an anvil holding cylinder 32 and an anvil plate 34 mounted on the anvil holding cylinder 32.

[0035] The die plate 30 and the anvil plate 34 are mounted on the tool holding cylinder 28 or the anvil holding cylinder 32, respectively, by magnetic force, for example.

[0036] The tool cylinder 24 and the anvil cylinder 26, more specifically the die plate 30 and the anvil plate 34, are configured in the example substrate 22 shown in Figure 3) to cut the substrate 22 into blanks 36, a matrix 38 and waste particles 40. In this example, the waste particles 40 are insular sections which are inevitably present between adjacent blanks because of their shape.

[0037] In the example of Figure 3, the matrix 38 is present only at the periphery of the substrate 22. but other forms of the matrix are possible, in particular extending between adjacent blanks 36.

[0038] At least two blanks 36 are positioned adjacent to each other so that adjacent blanks 36 are divided by a single cut 42. For this purpose the die plate 30 has cutting means 44, for example in the form of edges, blades or knifes, while the anvil plate 34 has complementary solid counter means 46 to facilitate well defined cuts 42.

[0039] In an alternative embodiment, the die plate 30 and / or the anvil plate 34 have cutting means 44, while die plate 30 and / or the anvil plate 34 have complementary solid counter means 46 to facilitate well defined cuts 42.

[0040] The waste particles 40 in this example are referred to as being “insular sections” as they are not connected to the matrix 38; they are isolated therefrom by the blanks 36 and have to be removed from the blanks.

[0041] As the waste particles 40 are not connected to the matrix 38, the waste particles 40 cannot be stripped by removing the matrix 38 but have to be stripped individually.

[0042] For this purpose, the anvil plate 34 has stripping means 48 located at the position where the waste particles 40 are formed.

[0043] In the embodiment shown, the stripping means 48 are stripping needles.

[0044] In an alternative embodiment, the stripping means 48 may be stripping pins or of any other design which fits the purpose.

[0045] Further, in the embodiment shown, the stripping means 48 form an integral, i.e. monolithic, part of the anvil plate 34.

[0046] For example, the stripping means 48 may be edged and / or milled similar to the cutting means 44 and counter means 46.

[0047] In a further alternative, the stripping means 48 may be separate from a base of the die plate 30 and fixed to the base, for example in holes drilled into the base.

[0048] In the embodiment shown, the die plate 30 has counter stripping means 50 positioned complementary to the stripping means 48, to facilitate the stripping means 48 piercing and thus consequently stripping the respective waste particles 40.

[0049] The counter stripping means 50 may be elastic and formed by an elastomer. In an alternative embodiment, the counter stripping means 50 are solid.

[0050] In all embodiments, there may be a small gap (e.g. 0.05 to 0.1 mm) between the stripping means 48 and the corresponding counter stripping means 50 to reduce the forces during the stripping process.

[0051] In a further alternative embodiment, the die plate 30 and / or the anvil plate 34 have stripping means 48, in particular while die plate 30 and / or the anvil plate 34 have complementary counter stripping means 50.

[0052] Further, the die plate 30 has a maximum thickness t of 0.6 mm while the anvil plate 34 has a maximum thickness T of 1 mm.

[0053] Generally, the die plate 30 and the anvil plate 34 each may have a maximum thickness t, T of any value.

[0054] However, the plate 30, 34 comprising the stripping means 48 may have a larger maximum thickness t, T than the plate 30, 34 without any stripping means 48.

[0055] In addition or in the alternative, the maximum thickness t of the die plate 30 may be less than the maximum thickness T of the anvil plate 34 by at least 25%.

[0056] Basically, the stripping means 48 should protrude far enough into the area where the substrate 22 is located during operation so that the stripping means 48 can reliably get a hold of the respective waste particles 40.

[0057] In one embodiment, the stripping means 48 protrude at least 0.3 mm into the area where the substrate 22 is located during operation.

[0058] In all configurations, the die plate 30 and / or the anvil plate 34 can comprise creasing means, e.g. in the form of creasing lines and / or counter creasing lines, to crease the blanks 36 in a well-defined way.

[0059] Generally, the stripping means 48 may be part of the tool cylinder 24 and / or the anvil cylinder 26 as long as they are configured to effectively strip the waste particles 40 during operation.

[0060] The same is true for the counter stripping means 50. In this context, the rotary cutter unit 20 comprises a stripping device 52 (see Figure 1) for removing the waste particles 40 from the stripping means 48 to keep the stripping means 48 clean and thus effective.

[0061] In one embodiment, the stripping device 52 comprises a brush that wipes the stripping means 48 clean.

[0062] In an alternative embodiment, the stripping device 52 comprises an air blower that creates an airstream to strip the waste particles 40 off the stripping means 48.

[0063] The airstream may also be used to transport the stripped of waste particles 40 along a duct and into a collating container.

[0064] During operation, the stripping means 48 will take hold of the waste particles 40 and thus remove them from the blanks 36 and the matrix 38, so that these waste particles will not be transported together with the blanks 36.

[0065] Afterwards, the waste particles 40 will fall off of the stripping means 48 or be stripped off by the stripping device 52 so that the stripping means 48 are ready to pick up a further waste particles 40 in the next round.

[0066] In Figure 4, another example of a substrate 22 is shown. For features known from the example of Figure 3, the same reference numerals are being used and reference is made to the above comments.

[0067] The difference between the two examples is that in the example of Figure 4, waste particles 41 are shown which can also be removed with the stripping means 48. The waste particles here are windows within a blank 36.

[0068] In an embodiment not shown, the waste particles can be narrow strip between adjacent blanks. The narrow strip can be used as a “tolerance band” between adjacent blanks if there is print on a first side of the cut and no print on the second side of the cut. The narrow strip cut between the adjacent blanks avoids white lines on the first side or thin printed lines on the second side. The narrow strips can also be removed from the blanks with the stripping means 48.

[0069] The assembly 10 may be part of a printing and rotary die-cutting inline process which further comprises one or more of the following sections: - A feeder which stacks and squares incoming substrates 22 before introducing them into the process at the required speed.

[0070] - A waste stripping section, in particular to remove the matrix 38 from the blanks 36. - A bundle stacker comprising a stacker and lift-table with four squaring sides which separate multi-ups and form bundles of blanks 36.

[0071] - A breaker and turntable for the creation of optimum palletization patterns.

[0072] In all configurations, the assembly 10 is configured to carry out printing and rotary die-cutting to produce complex blanks 36 for packaging or displays in a single pass and at high speed.

[0073] If the inline process comprises a waste stripping section, this sections may be substantially reduced in size and complexity compared to waste stripping sections known in the prior art due to the design of the rotary die cutter unit 20 which includes waste stripping functionality. In a further embodiment, the rotary die cutter unit 20 is part of a line without any printing units, for example an offline sheet to blank unit.

[0074] In this way, a rotary die cutter unit 20 as well as an assembly 10 with such a rotary die cutter unit 20 are provided which are highly efficient at producing blanks from a substrate with minimal waste.

Claims

Claims1. A rotary die cutter unit (20) comprising an anvil holding cylinder (32) and an anvil plate (34) mounted on the anvil holding cylinder (32), a tool holding cylinder (28) and a die plate (30) mounted on the tool holding cylinder (28), wherein the die plate (30) is configured to cut a substrate (22) into blanks (36), characterized in that the die plate (30) and / or the anvil plate (34) comprises stripping means (48) for stripping waste particles (40; 41) from the blanks (36).

2. Rotary die cutter unit (20) according to claim 1 , characterized in that the stripping means (48) are stripping pins or stripping needles.

3. Rotary die cutter unit (20) according to claim 1 or 2, characterized in that the stripping means (48) are a monolithic part of the die plate (30) or the anvil plate (34).

4. Rotary die cutter unit (20) according to any of the preceding claims, characterized in that the die plate (30) and / or the anvil plate (34) comprises counter stripping means (50) arranged complementarily to the stripping means (48) so that waste particles (40; 41) are located between a stripping means (48) and a corresponding counter stripping means (50) when the stripping means (48) contacts the respective waste particle (40; 41).

5. Rotary die cutter unit (20) according to claim 4, characterized in that the counter stripping means (50) are elastic.

6. Rotary die cutter unit (20) according to any of the preceding claims, characterized in that the maximum thickness (t) of the die plate (30) is different from the maximum thickness (T) of the anvil plate (34).

7. Rotary die cutter unit (20) according to any of the preceding claims, characterized in that the maximum thickness (t) of the die plate (30) is less than the maximum thickness (T) of the anvil plate (34).

8. Rotary die cutter unit (20) according to claim 7, characterized in that the maximum thickness (t) of the die plate (30) is by at least 25% less than the maximum thickness (T) of the anvil plate (34) .

9. Rotary die cutter unit (20) according to any of the preceding claims, characterized in that the rotary die cutter unit (20) comprises a stripping device (52) for stripping the waste particles (40; 41) from the stripping means (48) during operation.

10. Assembly (10) comprising at least one printing unit (12) and a rotary die cutter unit (20) according to any of the preceding claims.

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