HK1072745B - Folding apparatus in a web-fed rotary printing press - Google Patents

Description

Folding device in rotary printing machine

Technical Field

The invention relates to a folding device in a rotary printing press.

Background

In a rotary printing press, the material web to be printed is drawn off from a paper roll, printed in one or more printing units and fed into a folding unit, where the material web is divided into individual signatures by a cutting unit and then folded transversely by a folding blade mounted on a folding blade cylinder.

In this case, the signatures must be always fed to the folding-blade cylinder and/or to the folding-blade cylinder or to the transport cylinder of the folding apparatus in a controlled manner during the cutting process and the subsequent transport, in order to ensure that the front corners of the signatures are not chamfered and that the signatures are precisely located at predetermined positions.

In this connection, it is known from US 5,484,379 to provide a first cutting cylinder in front of the folding blade cylinder, which has a segmented cutting blade with an intermediate space, which provides the printing material web with a plurality of first partial slits at a distance from one another. The signatures are conveyed onto the folding-blade cylinder during the cutting process and during the subsequent conveying process through these intermediate chambers and around a circulating conveyor belt of the following folding-blade cylinder. In a second cutting process, a further cutting cylinder, which also has a cutter with a further intermediate space, produces second partial cuts in the printing material web, which partial cuts form successive cuts in a complementary manner to the first partial cuts. In this case, the signature passes in a corresponding manner through a plurality of further conveyor belts which pass through further intermediate chambers in the second cutting knife, wherein the folding-knife cylinder serves as a bearing element or anvil for the second cutting knife. In addition to the high number of components, the problem arises that, in the event of slight changes in the position of the signature after the first cutting operation, the signature edge itself is not continuously smooth, and therefore generally requires finishing, because the first and second partial slits are produced in the printing material web one after the other.

Disclosure of Invention

The object of the present invention is therefore to provide a folding device for a rotary printing press, which ensures a controlled guidance of the signatures during the cutting process and during the transport through the folding device, while reducing the number of components.

According to the invention, the object is achieved by a folding device for folding signatures in a rotary printing press, which signatures are cut off from a continuous web of printing material by a cutting device and are transported around a cylinder on a signature transport surface of said cylinder by means of at least one circumferential web-like transport element, wherein the cutting device comprises a cutting blade mounted on the cylinder and a rotary anvil interacting with the cutting blade, wherein the circumferential web-like transport element is guided around the rotary anvil and acts as a counter-pressure element for the cutting blade during the cutting of the signatures.

Other features of the invention may be obtained from further embodiments.

According to the invention, a folding device for folding signatures cut off by a cutting device from a continuous web of printing material printed in a rotary printing press comprises a cylinder, in particular a folding knife cylinder or a transport cylinder or a collector cylinder, on the circumferential surface of which, hereinafter referred to as signature transport surface, the signatures are transported by means of at least one circulating web-like transport element. In this case, the cutting device according to the invention has a cutting knife which is arranged on the folding-knife cylinder and interacts with a rotating or revolving anvil, preferably in the form of a cutting-knife cylinder. The circulating belt-like transport element runs around the rotary anvil in such a way that the former acts as a support element or counter-pressure element for the cutting blade during the cutting of the signature.

Here, the circulating belt-like conveying element can, for example, rest directly on the circumferential surface of the rotary anvil and run around the latter.

In the same manner, however, it is also possible for the circulating belt-like conveying element to be guided completely or partially around the circumference of the rotary anvil and additionally on the guide rollers. In this connection, it has proven to be particularly advantageous to arrange the guide rollers in such a way that, viewed with reference to the center of rotation of the folding-blade cylinder, the circulating web-shaped transport element is guided over the circumference of the folding-blade cylinder over an angular range of approximately 5 ° to 40 ° upstream of the point of interaction of the cutting blade with the rotary anvil, and the printing material web located between the circumferential surface of the folding-blade cylinder and the transport element is held so as to be so-called sandwiched in this range before the cutting operation. The vibrations of the material web caused by the cutting process can be greatly reduced by this.

However, the same arrangement can also be used if the printing material web enters substantially tangentially between the anvil and the folding-blade cylinder.

The invention has the advantage that the signature can be reliably guided even at high speeds without the signature advance angle being disadvantageously folded after the cutting operation by the wind generated during the advance and causing jamming or even damage to the folding device. In addition, the advantage of the device according to the invention is that, due to the use of a cutting device with a cutting blade extending over the entire width of the printing material web, it is in principle determined that the cutting edge of the signature is straight and smooth, rather than having a step as in the devices of the prior art, in which the first and second partial cuts are carried out one after the other, the signature cannot be precisely guided by the web, for example due to vibrations, for example, and thus a step is produced.

In an advantageous embodiment of the invention, the belt-like transport element is formed as a belt, which is preferably guided in a groove formed in the rotary anvil, wherein the depth of the groove is slightly smaller than the thickness of the belt. Although it is possible to use not only one strip, but a plurality of strips arranged next to one another at a distance from one another in a known manner, the invention will be described below for the sake of simplicity only by way of example as a strip.

According to a first embodiment of the invention, the belt is designed as a toothed belt, which is provided with reinforcing sections or inserts, for example made of metal or Kevlar (Kevlar), in the region of the cutter cooperating therewith during the cutting process, the cutter pressing onto these reinforcing sections during the cutting process in order to cut the printing material web located therebetween. This gives the advantage that, if the reinforcing segments are only placed on the smooth surface of the toothed belt, the internal structure of the belt, in particular the longitudinal strip for taking up the tensile forces, can remain unchanged, so that a conventional toothed belt can be used which is inexpensive and only needs to be slightly modified in its structure.

In this case, the reinforcing segments are preferably arranged at a distance from one another corresponding to the cutting length of the signature, which in the event of a slip between the toothed belt and the circumferential surface of the folding-blade cylinder increases by a value corresponding to the width of the gap which is produced during the rotation of the folding cylinder as a result of the slip between the leading edge of the printing material web or the trailing signature and the trailing edge of the preceding signature.

In an advantageous embodiment of the invention, the reinforcing segments are each provided with a cutting groove, into which the associated knife of the knife drum projects during the cutting operation. The advantage obtained by providing an additional groove in the reinforcing section of the toothed belt is that the cut edge of the signature can be formed very precisely and smoothly even when handling multi-layer signatures.

The toothed belt is guided with its toothed side around a rotating anvil, preferably designed as a cylinder, and with its flat rear side around the folding-blade cylinder, wherein the toothed belt is preferably driven by the anvil via a toothed section formed on the rotating anvil, in which the toothed side of the toothed belt engages. This has the advantage that the toothed belt moves with a high degree of phase stability relative to the anvil, by means of which a high degree of accuracy in maintaining the cut-out register can be achieved.

In an advantageous embodiment of the invention, the toothed belt, or more generally the revolving conveying element, moves at a lower speed than the folding-blade cylinder signature conveying surface. Here, the speed is such that: after the cutting process, as the folding-blade cylinder continues to rotate forward, a gap arises between the cutting blade and the leading edge of the printing material web, which gap is produced by the sliding between the signature transport surface of the folding-blade cylinder and the cut signatures carried at a relatively low speed by the toothed belt or the encircling transport element.

Advantageously, a leading edge gripper is arranged on the cylinder, which grips the leading edge of the signature cut from the printing material web through the gap formed.

Because of the gap which is produced in this way as the folding-blade cylinder rotates forward between the rear edge of the cutting element or of the preceding folding mark and the leading end of the printing material web guided around the circumference before the cutting-off of the following folding mark, the advantage is obtained that the front edge of the printing material web held on the circumferential surface of the folding-blade cylinder by the circulating transport element can be gripped by a front-edge gripper which grips the front edge of the printing material web through the gap before the cutting-off of the folding mark. The leading edge gripper device can be a known gripper device, which presses and grips in an advantageous manner the leading edge or leading edge of the printing material web against a gripper support surface extending at an angle inward. The gripper is preferably closed at the same time or shortly after the signature is cut off from the printing material web by the cutting device. The signature thus reaches the peripheral speed of the tucker blade cylinder immediately after the closing of the clamping device and is held in a known manner by the clamping device during the subsequent known folding process if the tucker blade pushes the signature into the associated folding blade of the following folding blade cylinder.

In the device according to the invention, the clamping device can only be brought into a sufficient position by the sliding according to the invention between the signature and the circumferential surface of the folding-blade cylinder in order to be able to exit from the circumferential surface of the folding-blade cylinder and to grip the leading edge of the printing material web in a reliable manner.

In an advantageous embodiment of the invention, the ratio of the speed of the transport surface of the folding-blade cylinder to the speed of the circulating band-shaped transport element corresponds to the quotient of two natural numbers, in order to ensure that the cutting elements on the folding-blade cylinder meet a reinforced section of the toothed belt again after a complete revolution of the folding-blade cylinder. In a corresponding manner, this also applies to the relationship of the respective length of the transport surface or circumferential surface of the folding-blade cylinder to the length of the circulating transport element. Here, the number n corresponding to the length of the transport surface may be, for example, in the range of 1 to 5 unit lengths, preferably 3 unit lengths, while the number m corresponding to the length of the circulating transport element is, for example, in the range of 1 to 3 unit lengths, preferably 1 unit length. If a unit length is referred to herein, it is particularly the length of the largest signature size that can be handled. But the numbers and unit lengths may have other values.

The cutting element can be arranged, for example, on the folding-blade cylinder in a stationary manner and can be protected by a protective and clamping device made of a rubber-elastic material, for example, polyurethane, arranged on both sides of the cutting element and projecting radially beyond the tip of the cutting element. This offers the advantage that the protective and clamping device automatically presses the printing material web against the anvil cylinder or against the corresponding reinforcing section surrounding the transport element during the cutting process and fixes it there.

According to a further embodiment of the inventive concept, the cutting element or the cutting blade is not fixedly mounted on the folding-blade cylinder but can be moved back into its circumference. This can be achieved, for example, by a control cam, which is used in a familiar manner for driving the folding blade, and a cam follower, wherein the control cam is arranged in a stationary manner and the cam follower is coupled to the cutting element in such a way that it is actuated by the rotation of the folding blade cylinder.

According to a further embodiment of the invention, a further endless web-like transport element is arranged downstream of the endless web-like transport element, as seen in the direction of rotation of the folding-blade cylinder, which further transport element, when using cutting elements which can be retracted into the circumference of the folding-blade cylinder, advantageously consists of a conventional transport belt known from the folding apparatus or of a plurality of transport belts which run parallel at a distance from one another in a familiar manner. The advantage is thereby obtained that the additional circulating transport element can be constructed at low cost as a standard component which has long been used in the construction of folding devices, whereas in this embodiment of the invention the transport element guided around the anvil is formed by a smooth-walled closure strip made of a material resistant to cutting over its entire length, for example kevlar or made of metal or another material resistant to cutting but elastic, which is comparatively complicated to produce. A further advantage is derived from the fact that the length of the first circulating smooth-walled belt of cut-resistant material can be chosen comparatively short, while the further circulating conveyor element, which is formed by a conventional conveyor belt or conventional conveyor belts, can have a comparatively large length without the costs being increased in a corresponding manner as a result.

Advantageously, the further circulating belt-shaped conveying element has a length which is increased by a factor of several times compared to the circulating belt-shaped conveying element.

In addition, the advantage obtained by selecting a comparatively short circulating conveyor belt made of a cut-resistant material is that it can circulate at a variable speed lower or higher than the circumferential surface of the folding-blade cylinder, in order to be able to arbitrarily increase or reduce the size of the gap which is produced between the rear edge of the cutting device or front signature and the front edge of the printing material web as a result of the speed difference. In this embodiment of the invention, the entire circumferential surface of the anvil element is advantageously formed as a cylindrical surface provided with corresponding grooves for the encircling cut-resistant band, which cylindrical surface is coated with a rubber-elastic material, for example polyurethane, which material acts as a cutting surface on the entire circumferential surface of the anvil element, which cutting surface interacts with the cutting element in the region of the encircling band-shaped conveying element, into which the cut-resistant band does not extend.

Advantageously, the further endless belt-shaped conveying element runs around at substantially the same speed as the endless belt-shaped conveying element.

Drawings

The invention is described below with reference to the drawings by way of advantageous embodiments.

The figures show that:

figure 1 is a schematic view of a folding unit according to the invention in a rotary press,

fig. 2a shows a schematic representation of a first embodiment of the cutting process, in which a toothed belt extending around the anvil and the folding-blade cylinder is used,

fig. 2b shows the embodiment of fig. 2a after the folding-blade cylinder has continued to rotate and the leading-edge clamping device has been closed, in order to clearly show the gap which is produced between the cutting element and the leading end of the printing material web,

figure 3 is an interrupted cross-section of the rotary anvil in the area of the position where the cutting element co-acts with the anvil,

figure 4 is a schematic view of a toothed belt passing through the grooves shown in figure 3,

figure 5 is a cross-sectional view of a toothed belt with two reinforcing segments arranged therein,

fig. 6 is another configuration of the belt-like conveying member, with a cutout groove formed therein and engaging holes formed thereon for phase-accurate driving,

FIG. 7 is a side view of another embodiment of the invention, in which a first endless belt-like conveying element and a further endless belt-like conveying element arranged behind it are used,

fig. 8a is an enlarged detail of the embodiment shown in fig. 7, in a first position of the folding-blade cylinder, in which the cutting element interacts with the anvil and cuts the signature off the incoming printing material web,

fig. 8b shows the embodiment of fig. 8a in another position after the folding-blade cylinder has continued to rotate and the front-edge holding device has been closed, for the sake of clarity of the resulting gap,

fig. 9 is a schematic perspective view of an advantageous embodiment of the cutting element, enclosed by the protection and clamping device,

fig. 10 is a perspective view of the anvil with a channel formed therein, through which a smooth-walled belt-like conveying member made of cut-resistant material passes,

fig. 11 is a top view of the embodiment of fig. 7, in order to clearly show the arrangement of the holding devices around the conveying elements and between them for gripping the front edge of the signature.

Detailed Description

As shown in fig. 1, the folding device 1 according to the invention for folding signatures 2 comprises a folding blade cylinder 8 which is cut off from a continuous web of printing material 6 by a cutting device 4 and has a signature transport surface 10 on which the signatures 2 are transported by means of a circulating web-shaped transport element 12.

The cutting device 4 comprises a cutting blade 14, which is arranged on the folding-blade cylinder 8, and a rotary anvil 16, which interacts with the cutting blade and is preferably in the form of a cylinder as shown in fig. 1, around which a web-shaped transport element is guided, so that during the cutting of the signature 2 the web-shaped transport element acts as a counter-pressure element or support element for the cutting blade 14, which in turn is supported on a corresponding portion of the rotary anvil 16. Here, the support on the rotary anvil 16 can be realized, for example, by a slotted strip 18 attached to the anvil or by a cutting rubber, as shown in fig. 4.

As shown in fig. 3 and 4, at least one groove 20 is formed in the rotary anvil 16, in which the circumferential belt-shaped conveying element 12 is guided, wherein the depth of the groove 20 is slightly smaller than the thickness of the belt-shaped conveying element 12. If a plurality of parallel, side-by-side, circumferential, belt-like conveying elements 12 are used according to a preferred embodiment of the invention, a corresponding number of grooves 20 are arranged at corresponding mutual distances across the width of the rotary anvil 16.

According to the embodiment of fig. 2a, 2b and 4, the circulating transport element can be formed by a toothed belt 22 which runs with its toothed side around the rotary anvil 16 and with its flat side around the folding-blade cylinder 8 and which is driven by means of teeth 24 on the circumferential surface of the rotary anvil 16.

As shown in fig. 5, the toothed belt 22 is provided with reinforcing segments or inserts 26 which have cutting grooves 27 into which the cutters 14 project during cutting. The reinforcing segments 26 are arranged at a distance D from one another, which corresponds substantially to the length of the signature 2 and includes the width B of the gap 28, the gap 28 being formed between the front edge 30 of the printing material web 6 and the cutting blade 14 of the cutting device 4, since the folding-blade cylinder 8 moves at a higher circumferential speed than the toothed belt 22.

As can be seen from fig. 2a, in the first roller position in which the signature 2 is cut out of the material web, a leading edge gripper 32 is operated, which passes through the gap 28 and grips the printing material web 6 or the leading edge 30 of the signature 2 that has just been formed or was formed shortly before. The signature gripped by the front-edge gripper 32 at the front edge 30 is then pushed in a known manner by a folding blade, not shown, into a folding plate, also not shown, of a rear folding-plate cylinder.

The speeds of the folding-blade cylinder 8 and of the belt-like transport element 12 or toothed belt 22 are selected here, for example, such that a gap 28 of between, for example, 1cm and 5cm results after a quarter revolution of the cylinder 8.

As shown in fig. 6, instead of the toothed belt 22, it is also possible to use a further belt-like conveying element 36 provided with engagement openings 34, which can be embodied, for example, as a metal belt or a kevlar belt, on which the cutting groove 27 is preferably formed, and which is driven by corresponding pin-shaped engagement elements, not shown, on the rotary anvil, which engage in the engagement openings 34.

According to a further embodiment of the invention, which is shown in fig. 7, the band-shaped circulating conveyor element is formed as a band 38 made of a cut-resistant material, preferably with smooth walls, downstream of which a further circulating band-shaped conveyor element 40 is arranged in the direction of rotation of the folding-blade cylinder 8. Here, the belt 38 is guided around the rotary anvil 16 by guide rollers, not numbered in detail, in such a way that: the circulating web-like transport element 38 is guided, as viewed with reference to the center of rotation of the folding-blade cylinder 8, over an angular range of approximately 40 ° upstream of the point of interaction of the cutting blade 14 with the rotary anvil 16, as viewed in the transport direction, over the circumference of the folding-blade cylinder 8, and the printing material web 6 lying between the circumferential surface of the folding-blade cylinder 8 and the transport element 38 is held in this range before the cutting operation.

The imaginary tangential entry direction of the printing material web is shown by dashed lines.

In this case, the belt 38 runs around at a speed which is preferably slower than the speed of the signature transport surface 10 of the folding-blade cylinder 8, in the same way as the further revolving transport element 40, by which, in the same way as in the embodiment shown in fig. 2a and 2b, a gap 28 is produced between the leading edge 30 of the printing material web 6 and the cutting knife 14, through which gap a leading-edge holding device 32 grips the leading edge 30 as shown in fig. 8a and 8b as the cylinder 8 continues to rotate, and thus guides the signature 2 at the speed of the cylinder signature transport surface 10 after the cutting process.

In the same way as the toothed belt 22, a belt 38 made of a cut-resistant material is also guided in the associated groove 20, which is formed on the circumference of the rotary anvil 16.

As can be seen from fig. 11, when a plurality of belts 38 made of cut-resistant material running side by side and a plurality of further endless conveying elements are used, which are each arranged staggered relative to one another, the front edge gripping device 32 is advantageously arranged centrally between the further conveying elements 40 arranged behind, at the level of the belts 38.

Fig. 9 finally shows an advantageous embodiment of the cutting blade 14, which is laterally provided with a protective and clamping device 42 made of a rubber-elastic material, for example, polyurethane. The protective and clamping device 42 serves, on the one hand, to prevent damage due to the cutting knife 14, which is preferably mounted in a stationary manner on the circumference of the folding-knife cylinder 8, and, on the other hand, to press the newly produced leading cutting edge of the printing material web 6 against the rotary anvil 16 and against the circulating web-like transport element 12, which acts as a counter-pressure element or support element, during the cutting operation.

Reference symbols

1 folding device 2 signature

4 cutting device 6 for printing material web

8 folding blade cylinder 10 signature transport surface

12-ring belt-shaped conveying element 14 cutter

16 rotary anvil 18 grooving strip

20-groove 22-tooth belt

24 reinforcement of the teeth 26 in the anvil

27 cutting groove 28 gap

30 front edge 32 front edge holding device for printing material belt

34 engaging holes 36 metal strap/Kevlar strap

38 strip of cut resistant material

40 additional circumferential band-shaped conveying elements

42 protection and clamping device

D the width of the gap 28 between the reinforcement segments 26

Claims (16)

1. Folding device (1) for folding signatures (2) in a rotary printing press, which signatures are cut off from a continuous printing material web (6) by a cutting device (4) and are transported around a cylinder on a signature transport surface (10) of said cylinder by means of at least one circumferential web-like transport element (12, 22, 36, 38), characterized in that the cutting device (4) comprises a cutting blade (14) arranged on the cylinder and a rotary anvil (16) interacting with the cutting blade, wherein the circumferential web-like transport element (12, 22, 36, 38) is guided around the rotary anvil (16) and acts as a counter-pressure element for the cutting blade (14) during the cutting of the signature (2).

2. A folding apparatus according to claim 1, characterized in that the web-like transport element (12, 22, 36, 38) is formed as a belt which is guided in a groove (20) formed in the rotary anvil (16), wherein the depth of the groove (20) is slightly smaller than the thickness of the web-like transport element.

3. A folding device according to claim 2, characterized in that the belt is formed as a toothed belt (22) which is provided with a reinforcement section (26) in the region with which the cutting knife (14) interacts during the cutting process.

4. A folding device according to claim 3, characterized in that each reinforcing section (26) is provided with a cutting slot (27) for accommodating the cutter (14) during cutting.

5. A folding apparatus according to claim 3 or 4, characterized in that the toothed belt (22) is guided with its toothed side around the rotary anvil (16) and with its flat side around the cylinder.

6. A folding apparatus according to one of claims 1 to 4, characterized in that the cutting blade (14) is fixedly arranged on the circumference of the cylinder.

7. A folding apparatus as claimed in claim 6, characterized in that the cutting blade (14) is covered on both sides by a protective and clamping device (42) made of a rubber-elastic material for preventing injuries and for clamping the leading edge (30) of the printing material web (6).

8. A folding apparatus according to one of claims 1 to 4, characterized in that the circulating conveyor elements (12, 22, 36, 38) circulate at a reduced speed compared to the signature conveying surface (10) in such a way that: after the cutting process, a gap (28) is formed between the cutting blade (14) and the front edge (30) of the printing material web (6) as the cylinder continues to rotate forward.

9. A folding device according to claim 8, characterized in that a leading edge holding device (32) is provided on the cylinder, which leading edge holding device grips the leading edge (30) of the signature (2) cut from the printing material web (6) through the formed gap (28).

10. A folding apparatus according to claim 8, characterized in that the ratio of the speed of the transport surface (10) of the cylinder to the speed of the circulating band-like transport elements (12, 22, 36, 38) is n/m, where n and m are each natural integers.

11. A folding apparatus according to one of claims 1 to 4, characterized in that a further endless belt-like transport element (40) is arranged downstream of the endless belt-like transport element (12, 22, 36, 38), viewed in the direction of rotation of the cylinder.

12. A folding apparatus according to claim 11, characterized in that the circumferential band-like transport elements (36, 38) are made of a material which is resistant to damage by the cutter (14) over their entire length, and that the further circumferential band-like transport elements (40) are made of a material which is not resistant to cutting.

13. Folding apparatus according to claim 11, characterized in that the further circulating band-shaped transport element (40) has a length which is increased by a factor of several times compared to the circulating band-shaped transport elements (12, 22, 36, 38).

14. Folding apparatus according to claim 11, characterized in that the further circulating band-shaped conveying element (40) runs around at substantially the same speed as the circulating band-shaped conveying elements (12, 22, 36, 38).

15. A folding apparatus according to one of claims 1 to 4, characterized in that the circulating band-shaped transport elements (12, 22, 36, 38) are guided around the rotary anvil (16) by guide rollers in such a way that, viewed in the direction of rotation of the cylinder, the circulating band-shaped transport elements (12, 22, 36, 38) are guided against the circumference of the cylinder over a predetermined angular range, viewed in the conveying direction, upstream of the point of interaction of the cutting blade (14) with the rotary anvil (16).

16. A folding apparatus according to one of claims 1 to 4, characterized in that said cylinder is a folding blade cylinder (8) or a transport cylinder.