EP1268329A2

EP1268329A2 - Device for cutting paper webs

Info

Publication number: EP1268329A2
Application number: EP01921304A
Authority: EP
Inventors: Dieter Brückel; Helmut Eichelberg; Otto Hartmann
Original assignee: Boewe Systec AG
Current assignee: Boewe Systec AG
Priority date: 2000-03-07
Filing date: 2001-03-02
Publication date: 2003-01-02
Anticipated expiration: 2021-03-02
Also published as: JP2003526586A; EP1268329B1; WO2001066448A3; DE10011006A1; WO2001066448A2; ATE256063T1; DE50101139D1; US20030089209A1; ES2208583T3

Abstract

The invention relates to a device for cutting paper webs. Said device comprises a paper feed device (102), a cutting device (108) and a paper delay device (106) which is located between the paper feed device (102) and the cutting device (108) and which delays the fed paper web (112) in such a way that a position is determined on the paper web (112) in which the cutting device (108) is to cut the paper web (112). A buffer device (104) is located between the paper feed device (102) and the paper delay device (106) to take up an accumulating length of the paper web (112) in the form of a loop whilst said web (112) is delayed. A control device (190) controls the paper feed device (102) and the paper delay device (106) in such a way that the height of the loop (195) taken up by the buffer device (104) does not fall below a minimum threshold (h).

Description

Device for cutting paper webs

description

The present invention relates to an apparatus for cutting paper webs according to the preamble of claim 1. In particular, the present invention relates to an apparatus for cutting paper webs which forms part of a complex paper handling system.

Paper handling systems are mainly used by large companies, banks, insurance companies, service companies, etc. At these companies, the paper handling systems are used to process large quantities of paper, such as invoices, reminders, bank statements, insurance policies or checks. The individual papers to be handled by such a paper handling system are in many cases produced by high-speed printers which print letters, forms etc. on a paper web. This paper web will typically be fed to the printer from a large supply roll and will be fed to the paper handling system after printing. However, before the paper handling system can perform the appropriate operations for assembling individual papers, etc., it is necessary to cut the paper web printed by the high speed printer so that individual sheets are fed to the paper handling system. For this purpose, cutting machines are used which have a knife or some other type of cutting device, the paper web to be cut being fed to the knife by means of a paper feed device. These paper handling systems are often designed in such a way that handling different papers with different formats is made possible. This flexibility in the formats used by the paper handling system requires that paper webs can be cut in different formats.

Another important point in paper handling systems is that depending on the control of these handling systems, different numbers of papers are required for the respective processes, that is to say that five additional pages are added to a specific letter, whereas only another page is added to another letter got to. In order to ensure feeding at a different rate, it is necessary that the cutting machine is not only able to cut different formats, but also to feed them to the paper handling system at different speeds.

The cutting systems listed above, which form part of a complex paper handling system, therefore fundamentally meet different requirements than so-called rotary cutting machines, such as those used in print shops for the production of daily newspapers. Such rotary cutting machines only serve to cut paper webs in a predetermined format. By specifying only one format, it is possible with these machines to drive the paper web to the rotary knife at a constant speed, the drive speed being determined as a function of the fixed format and the rotary speed of the rotary knife. The changeover to a different format is associated with considerable effort in such rotary cutting machines, since the drive speed of the rotary knife and the feed speed of the paper web have to be adjusted depending on the new format. With such rotary cutting machines, automatic setting of the respective parameters to a new format is required a considerable control effort.

In addition to the systems described above, cutting machines are also known in the prior art in which the paper web is advanced by a desired cutting length 1 by means of a drive over the cutting edge of a cross cutting device, which can be formed by a lifting or rotating knife, and held in the cutting position , While the paper is now in the cutting position, the cross cutting device cuts off the paper that is fed over the cutting edge. In order to obtain a high throughput (cuts per hour), the paper web must be advanced by the cutting length in the shortest possible time so that the paper web is again in the desired cutting position. In order to achieve this, the paper web must be accelerated to a maximum speed V _{ma möglichst} in the shortest possible time and braked again in such a way that exactly the cutting length 1 was advanced when the paper web came to a standstill.

The disadvantage of this procedure is that the very high acceleration and the very high maximum speed cause a very restless movement of the paper web when it is fed into the machine. This also leads to errors in the paper feed due to creasing or even tearing of the paper web. This limits the maximum possible acceleration and the possible maximum speed. Such a cutting machine is described in more detail in FIG.

The cutting machine 500 includes a paper feed device 502 which is driven by a motor 502a. As can be seen in FIG. 5A, the paper feeding device 502 includes a first drive roller 504 which is driven by the motor 502 at a speed V * _j _. A feed element, preferably in the form of a feed belt 508 or a feed chain, is guided through the drive roller 504 and a guide roller 506. A paper web 512 extends from a storage area 510 via a diverter and guide device 514 to the feed device 502.

In the cutting machine shown in FIG. 5A, the paper web 512 is provided with a perforated edge, in which evenly spaced holes for guiding and driving the paper web are provided. To ensure the drive and guidance of the paper web 512, the guide belt 508 of the feed device 502 has a plurality of teeth 508a which engage with the holes in the perforated edge of the paper web 512. The paper web 512 is fed to a cutting device 516 by means of the feed device 502. The cutting device 516 comprises a so-called drop knife 518, which is essentially in the form of a guillotine. This drop knife is movably guided between two guides 520, 522. The cutting device further comprises a counter cutting edge 524, against which the drop knife 518 moves in the direction perpendicular to the paper web 512 during its cutting movement. The drop knife 518 is actuated by means of a motor 526 which, for example, drives a belt drive consisting of a drive roller 528a, a guide roller 528b and a belt 530 at a speed V2. At an eccentric position of the guide roller 528b, one end of a connecting rod 532 is attached, the opposite end of which is connected to the drop knife 518. In combination with the drive 526, the connecting rod 532 and the guides 520, 522, the drop knife executes a continuous up and down movement when the motor 526 is driven. In the paper running direction after the cutting device 516, a paper discharge device 534 is provided, which serves to move the cut pieces of paper further. This paper discharge device comprises a drive roller 538 actuated by a motor 536. The motor 536 drives the drive roller 538 at a constant speed V ₃ . In general, the speed V3 of the drive roller 538 is higher than the feed speed of the paper web 512, so that the cut papers are reliably transported away. represents is. In addition to the drive roller 538, the paper discharge device 534 comprises a guide roller 540, the cut papers moving between the drive roller 538 and the guide roller 540. The guide roller 540 is biased by a spring 542 to press the paper and against the drive roller 538.

The basic operation of the cutting machine described in FIG. 5A is explained in more detail below with reference to the diagrams shown in FIGS. 5B and 5C.

At a time t = 0, the motor 502a is driven to the feeding means 502, so that the paper is accelerated to a speed V- _j _ to be driven. At time t _] _, the predetermined speed V * _j _ is reached and is maintained until time t ₂ . When the time t ₂ is reached, a position of the paper web 512 in which the cutting is to take place is already in the vicinity of the cutting device 516. The drive of the feed device is controlled in such a way that the paper web 512 is braked from the time t ₂ that this is stopped at time t ₃ . As soon as the time t _{3 is} reached, the motor 526 is driven and accelerated to the speed V ₂ , which is reached at the time t ₄ . This speed is maintained until time t ₅ and the speed is reduced to zero until time t ₆ . During the course of time from t ₃ to t ₆ , the upward and downward movement of the connecting rod 532 results in the cutting movement of the drop knife 518 and the paper web is cut at the desired position. The paper discharge device 534, which is continuously driven by the motor 538 at the speed V ₃ , ensures that the cut paper is transported further. As soon as the time tg has been reached, the control of the speeds described with reference to FIGS. 5B and 5C begins again and the paper web 512 is fed further in the direction of the cutting device 516 until the corresponding cutting position on the paper web 512 is reached. With the cutting machines described with reference to FIG. 5A, cutting capacities of up to 19,000 standard forms per hour or cuts per hour with dimensions of the resulting format of 304.8 (12 inches) × 210 mm can be achieved.

A disadvantage of the cutting machine described with reference to FIG. 5A is that its operation requires the constant acceleration of a large mass, namely the paper web. This constant acceleration and deceleration of the paper web does not allow continuous operation. These constant accelerations and decelerations mean that the service life of the components used, in particular of the motors 502a, 526 used, is considerably reduced. The achievable accelerations or decelerations and thus the achievable cutting capacities are also limited by the fact that when the accelerations are too high, the edges of the guide holes are torn off or the paper web is torn off in the case of cross-perforated material. Furthermore, the jerky acceleration of the paper mass fed leads to a high noise emission.

Another problem that these known cutting machines have is that due to the low paper running speed, which is limited by the constant acceleration and deceleration, the suitability for a so-called online operation is not given. The term online operation refers to an operating mode in which a paper web is fed to a high-speed printer, this is printed and fed directly to the cutting machine at the speed of the printer.

In the known cutting machines from the prior art, a supply stack 510 is therefore provided, into which the finished printed paper webs are introduced by a remote printer and are fed from there to the cutting machine. The low paper speed Speed also results in an upper limit on the performance of such known cutting machines, which is currently known machines at the approximately 19,000 standard forms per hour or cuts per hour with dimensions of the resulting format of 304.8 (12 inches) x 210 mm.

Another reason for the above-mentioned limitation of the performance of these known machines is that the performance of above 19,000 cuts per hour leads to chaotic phenomena of the paper web, which are caused by the constant acceleration and deceleration and cannot be suppressed or controlled technologically are.

Paper handling systems are already known in the prior art which continuously feed a paper web to be cut to a knife without stopping the paper web when cutting it.

DE-OS 2165194 relates to a method and a device for feeding material to sheet-processing and sheet-processing machines. A web of material is fed from a roll of material to a knife cylinder by means of a pulling section. The material web is cut in such a way that the material web is held on the knife cylinder by means of suction devices when reaching the knife cylinder and a so-called waste strip is first cut off and the front edge of the material web thus produced, which is still held by the suction cups, is turned on by the knife cylinder passed a guide cylinder. The front edge of the material web is held on the guide cylinder during a further rotation of the cylinder and conveyed at the web speed until the material web reaches a cutting area in which an arc is cut off by the knife. During operation, a loop is formed between the material roll and the knife, which is built up during the cutting process and after cutting is dismantled again.

DE-PS-723878 relates to a conveyor for webs, in particular paper webs, on cross cutters and folding machines. A paper web is fed evenly to a knife via rollers, a suction stamp being arranged between the knife and the rollers, which holds the paper web so that paper is not conveyed further in the direction of the knife. This holding action creates a loop due to the continuously fed paper.

However, the above-described paper handling systems that continuously feed a paper web to be cut during the cutting operation have a significant problem in cutting accuracy when the speed of the paper feeding exceeds a certain value. It was found that the cutting accuracy, the tolerances of which are in the tenths of a millimeter range, depend on the design of the paper loop. From a paper feed speed that is greater than 0.8 m / s, the loop shows a behavior that is no longer reproducible. This no longer reproducible behavior of the loop leads to unacceptable fluctuations in the cutting accuracy.

Other cutting machines known in the art, e.g. in DE 196 24 277 comprise a buffer device arranged between a paper feed device and a cutting device, which takes up the length of the paper web that has run up during the deceleration of the paper web and at the same time controls the formation of a loop of the run-up paper web and dampens the vibrations of the loop, and leads to reproducible loop behavior.

The disadvantage of this device just described is that the loop is stretched at high speed during the feed phase, so that despite the damping Do not let the cracker break away. Furthermore, each of these stretches represents a considerable mechanical load on the paper web, which is disadvantageous in that it entails the risk of the paper web tearing or leads to creasing, which leads to problems in feeding the paper web.

The present invention has for its object to provide an improved device for cutting paper webs, which has a high performance, is simple and inexpensive to implement, has high cutting accuracy at high paper feed speeds and the mechanical stress on the paper web reduced.

This object is achieved by a device according to claim 1.

The present invention provides an apparatus for cutting paper webs with a paper feed device, a cutting device, a paper delay device, a buffer device and a control device. The paper delay device is arranged between the paper feed device and the cutting device and delays the fed paper web in such a way that a position is fixed on the paper web at which the cutting device cuts the paper web. The buffer device is arranged between the paper feed device and the paper delay device in order to receive a running length of the paper web in the form of a loop during the delay of the paper web. The control device controls the paper feed device and the paper delay device in such a way that the loop accommodated in the buffer device does not fall below a minimum height.

Generally speaking, the present invention relates to a machine for cutting an endless paper web with and without transport hole edges, in which the paper web is advanced by a cutting length 1 over the cutting edge of a cross cutting device and is held in this position for the duration of the cut. The paper webs to be processed are either pre-folded as a stack, are unwound from a roll or are fed online by a printer.

The device according to the invention decouples the high dynamics of the paper feed for cutting from the paper feed into the machine and thus allows a higher acceleration and maximum speed when feeding the paper web into the cutting position within the machine with a significantly lower acceleration and maximum speed when feeding the paper web into the machine , If the device is operated in continuous operation, which is characterized by a continuous sequence of advancing and cutting, an almost continuous paper feed can be achieved. Furthermore, the fact that the loop is never completely dismantled, i.e. avoiding stretching of the paper, ensures that no unnecessary mechanical stresses are exerted by the stretching on the paper during the feed phase, so that the risk of errors due to tearing or creasing the paper web can be reduced.

An advantage of the present invention is that the errors just described, e.g. the creasing or tearing of the paper web can be further reduced by reducing the dynamics of the movement of the paper web as the paper is fed into the machine. Another advantage is that due to the avoidance of a complete stretching of the paper web in the feed phase, the noise generated by the paper web fed is reduced.

Another advantage of the present invention is that feeding the paper web with substantially constant speed is possible if the paper web is briefly decelerated to determine the position at which the cutting is to take place.

The advantage of the present invention is that, due to the uniform feed speed of the paper web, there is no longer any need to accelerate and decelerate the paper web, so that there is no need to constantly switch the motors on and off, which leads to a significant increase in the service life of these Motors and the other components leads.

Another advantage of the present invention is that the device according to the present invention can be run at a double paper running speed compared to the paper running speed in machines from the prior art. This leads to a doubling of the performance, which is 24,000 cuts per hour in devices according to the present invention.

Yet another advantage of the present invention is that by feeding the paper web at a constant speed, the device according to the present invention can be operated in a continuous mode, which means that it can connect directly to the output of a high speed printer so that the rearrangement and intermediate storage of the paper web is eliminated.

Preferred developments of the present invention are defined in the subclaims.

Preferred exemplary embodiments of the present invention are explained in more detail below with reference to the accompanying drawings. Show it:

1 shows a first exemplary embodiment of the device according to the invention; FIG. 2 shows an enlarged representation of the buffer device for the exemplary embodiment shown in FIG. 1;

3 shows a second preferred exemplary embodiment of the present invention;

4 shows an enlarged illustration of the buffer device for the exemplary embodiment shown in FIG. 3; and

5A-5C illustrate a cutting machine according to the prior art.

1, a first preferred exemplary embodiment of the present invention is described in more detail below.

1 shows the schematic representation of a cutting machine 100 according to a first exemplary embodiment of the present invention. The cutting machine 100 comprises a feed device 102, a buffer device 104, a conveying device 106 and a cutting device 108, which are arranged one after the other in a conveying direction, which is indicated by the arrows 110, of the paper web 112.

The feed device 102 comprises a pair of drive rollers 114a, 114b. The drive roller 114a is driven by a motor 116, as shown schematically by the connection 116a. The drive roller 114b is arranged on an "L" -shaped carrier element 118 which is rotatably supported by a bearing 120. The support element 118 and thus the drive roller 114b is prestressed via the bearing 120 against the drive roller 114a via a spring 122 and presses against the same.

Between the drive rollers 114a and 114b, the paper passed through web 112, which is driven by the two rollers 114a, 114b. The paper web 112 is fed from a paper supply (not shown), for example in the form of a pre-folded stack or a roll, in the direction of the feed device 102, which additionally has a deflection and guide plate 124 for properly feeding the paper web 112 to the feed device 102 having.

The buffer device 104 comprises a base plate 130 which extends essentially from the feed device 102 to the conveyor device 106. In the area in which the paper web is to be received in the buffer device, the base plate has a plurality of openings 132 which allow air to pass through. In the embodiment shown in FIG. 1, the paper web rests on the bottom panel 130 at least in the areas adjacent to the feed device 102 and the conveyor means 106, and air passes through the openings 132, which is generated by a fan 134 that is located below the bottom panel 130 is arranged in the area of the buffer device 104. The bottom plate 130 forms a lower guide device of the buffer device.

In addition to the base plate 130, the buffer device 104 comprises a first upper guide device 136 and a second upper guide device 138, which can each be designed as guide plates. The first guide plate 136 extends from the buffer device 104 to the feed direction 102 and is bent such that the guide plate 136 in the area of the buffer device 104 is arranged essentially perpendicular to the conveying direction 110 of the paper web 112 and essentially parallel in the area of the feed device 102 to the feed device 110. In a similar manner, the guide plate 138 extends from the buffer device 104 to the conveyor device 106, the guide plate 138 being bent such that it essentially extends in the area of the buffer device 104. are arranged perpendicular to the paper conveying direction 110, and in the region of the conveying device 106 is arranged essentially parallel to the conveying device 110 of the paper web 112.

The buffer device 104 further comprises a sensor device 140, which in the exemplary embodiment shown is formed by a light-emitting diode or a laser diode 140a, which is arranged adjacent to the guide plate 138. The diode 140a emits light in the direction of the first guide plate 136 and onto a reflective element 140b arranged thereon, which reflects the light beam back to a detector 140c, which in turn is arranged adjacent to the guide plate 138. The sensor device 140 serves to determine a height of the loop forming in the buffer device 104, a minimum and maximum loop height of the paper web being built up being shown by way of example in FIG. 1. The sensor device 140 detects a height h of the paper loop 195 in the buffer device 104 and outputs a corresponding detection signal to the controller 190. The "height" of the loop is the distance that it extends in a direction that is perpendicular to a plane in which the paper web 112 is fed and cut.

In Fig. 1, a second sensor device 150 is further shown, which is arranged between the buffer device 104 and the conveyor device 106, which comprises a light-emitting element 150a, such as e.g. a laser diode or a light emitting diode, and a detector element 150b. This sensor device can be used to detect the presence of a paper web and / or format recognition features arranged thereon, which serve to control the cutting device.

The conveyor device 106 is formed by a pair of drive rollers 160a, 160b, which is structurally similar to the drive roller pair 114a, 114b. A motor 162 drives the roller 160a, as shown schematically by the connection 162a. The drive roller 160b is arranged on an "L" -shaped carrier element 164 which is rotatably mounted at 166. The carrier element 164 and thus the drive roller 160b is biased against the drive roller 160a by means of a spring 168. The paper web 112 moves between the drive rollers 160a and 160b. The paper web is moved in the direction of the cutting machine 108 by the conveying device 106 and at the same time serves to display the paper web 112 when a cutting position is reached.

The cutting device 108, which is only shown schematically, comprises a lifting knife 170 which is guided by two guide devices 172, 174. The paper web 112 is passed between the knife 170 and a shear bar 176. Via an active connection 178, the knife 170 is connected to an actuating device 180, which in turn can be driven by a motor 182, as represented by the connection 182a.

The individual drive elements 116, 162 and 182 of the cutting device 100 are controlled by a control device 190, which on the one hand ensures that in the feed phase the paper web is advanced by the length 1, which represents the desired cutting length, and then the cutting of the Paper web is operated. On the other hand, the control device 190 ensures that the paper loop accumulated in the buffer device does not fall below the minimum height by a suitable control of the corresponding drive elements.

Furthermore, a paper discharge device - not shown in FIG. 1 - is provided, which is arranged downstream of the cutting device in the paper running direction. The paper discharge device comprises, for example, a pair of drive rollers between which the cut paper is guided. During operation, the paper web 112 is fed into the machine 100 and the paper web 112 is fed into the machine with a stop for cutting by the two separate drive units 102, 106, that is to say the drive “infeed” with a motor and the drive “feed” with Engine.

The "inlet" drive 102 pulls the paper web 112 into the machine 100 and conveys the paper web 112 into a loop 195 in the buffer device 104. The loop forms between the loop guide plates 136, 138 and when the loop reaches a maximum height, the control device effects 190 that the drive "inlet" 102 is stopped.

While the "feed" drive 106 conveys the paper web 112 under the cross-cutting device 108 with high acceleration and speed by the cutting length 1, the "feed" drive 102 simultaneously causes the paper web to be fed into the loop 195 of the buffer device 104.

The "feed" drive 106 preferably runs at a higher maximum speed than the "inlet" drive 102, so that the loop 195 between the guide plates 136, 138 initially breaks down. During the time that the "feed" drive 106 decelerates the paper web in order to cut off the fed web 112, the loop in the buffer device 104 builds up again.

The advantage of this arrangement is that the high dynamics of the paper feed for cutting is essentially limited to the paper web stored in the loop. The fan 134 supports an even and calm loop formation from below and at the same time dampens the movement of the paper in the loop.

The drive control or drive control 190 causes that while the paper web 112 from the drive "feed" 106 to a cutting length 1 is advanced, the loop height does not fall below a minimum. In this way, undesired stretching and thus undesirable popping noises and an even more undesirable mechanical load on the paper web are reliably avoided.

According to a further exemplary embodiment of the present invention, the control device 190 is further designed so that when a maximum loop height is reached, when the drive “feed” 106 is at a standstill, ie when cutting or when the cutting device 108 is stopped, a maximum height does not exceed.

In continuous operation of device 100, i.e. in the case of cyclical feed and cutting, the drive control 190 adjusts the feed speed in such a way that an almost constant speed of the incoming paper web 112 is established.

The advantage of the embodiment described in FIG. 1 is that, unlike the devices known from the prior art, this avoids complete stretching of the paper web during the feed phase of the paper web 112, and thus the disadvantages associated therewith. A further advantage is that, as can be seen, no additional stamp element or other stop element is provided, but the required paper delay is effected by the conveyor 106, by means of which the paper is delayed or stopped during the cutting process.

2 shows an enlarged illustration of the buffer device. Furthermore, the conveyor devices 102 and 106 arranged immediately before and after the buffer device are shown. In FIG. 2, the elements already described with reference to FIG. 1 are provided with the same reference symbols, and the same will not be described again. As can be seen, the drive roller is 114a of the feed device 102 is mounted on a shaft 200 on which a belt wheel 202 is arranged. The wheel 202 is connected to the motor 116 (not shown in FIG. 2) via a belt 116a.

Similarly, the drive roller 160a of the conveyor 106 is arranged on a shaft 204 which has a belt wheel 206 which is connected to the motor 162, not shown, via a belt 162a.

3, another preferred embodiment of the cutting machine according to the invention is shown below, which is similar to that of FIG. 1. Instead of the double action of the drive device 106 for conveying and decelerating the paper web, this exemplary embodiment realizes this functionality in two separate devices. Furthermore, the buffer device 104 additionally comprises a hood in order to further support the damping of vibrations. The functionality of the buffer device and the control of the individual motors is similar to the exemplary embodiment shown in FIG. 1, so that it is ensured that the paper loop in the buffer 104 does not fall below a minimum height.

The cutting machine 300 comprises a feed device 302, a cutting device 304 and a paper delay device 306 arranged between the feed device 302 and the cutting device 304. The paper feed device 302 feeds a paper web 308 at a substantially constant speed. The paper delay device 306 delays the feeding of the paper web 308 to the cutting device 304 such that a position is fixed on the paper web 308 at which the cutting device 304 performs the cutting of the paper web. The direction of paper travel is illustrated by arrow 310.

The feed of the paper web 308 can, for example, from a high speed printer (not shown). The feed takes place via a deflecting and guiding device 312. In the exemplary embodiment shown in FIG. 3, the paper web 308 is provided with a perforated edge in which holes are arranged which are evenly spaced and by means of which the paper web is driven and guided. The feed device 302 comprises a drive roller 314, a guide roller 316 and a feed element 318 guided by the drive roller 314 and the guide roller 316. The element 318 is provided with a plurality of teeth 318a which engage with the holes arranged in the perforated edge of the paper web 308 and guide and drive the paper web 308 in this manner.

A buffer device 320 is provided between the feed device 302 and the paper delay device 306, which serves to accommodate the length of the paper web that runs up during the delay of the paper web by the delay device. An example of the buffer device is described in more detail below with reference to FIG. 4.

The buffer device comprises a lower guide device 322, which is referred to as a bottom plate, and an upper guide device, which consists of two guide plates 324a and 324b. The paper web 308 to be cut moves between the lower and the upper guide device. Furthermore, the buffer device 320 comprises a cover 324c. Arranged on the lower guide device 322 are two nozzles 326a, 326b, through which air preferably exits. The nozzles are provided to inject air between the paper web 308 and the lower guide 322, while the paper retarder 306 delays the travel of the paper web 308 so that the paper web 308 rises smoothly without undesirable warping or kinking of the paper web 308 , The nozzles 326a, 326b can be controlled such that they are only active during the activation of the delay device and during the movement of the paper web 308 are not activated by the delay device 306.

The function of the lower and upper guide device and the hood is described below with reference to FIG. 4, in which the same elements are provided with the same reference numerals. The illustration of the nozzles has been omitted in FIG. 4 in order to maintain the clarity of the illustration.

The lower guide device 322 is formed by a base plate which is angled with respect to the plane of the paper feed in order to deflect the paper web 308 entering the buffer device 320 from the plane of the paper feed, thereby causing the formation of a loop. The bottom plate 322 is provided with a plurality of recesses 372, through which air, which is emitted from the nozzles (FIGS. 3, 326a and 326b), is introduced into the region between the bottom plate 322 and the paper web 308. This supports the formation of the loop 370 in addition to the effect of the angled bottom plate 322.

The upper guide device 324 serves to ensure that, in the event that the paper web 308 comes into contact with the upper guide device 324 due to the blown-in air, the paper web 308 can be guided safely to the paper delay device by the upper guide device 324. The upper guide device comprises a first guide plate 324a and a second guide plate 324b. The guide plates 324a, 324b each comprise a first section 374a, 374b, which are arranged at an angle with respect to the paper feed direction (arrow 376). As indicated by the arrows 378, the angle at which the first sections 374a, 374b are arranged is adjustable. Furthermore, the guide plates 324a, 324b each comprise second sections 380a, 380b, which extend essentially parallel to the paper feed direction 376 and are connected to the first sections 374a, 374b. The guide plates 324a, 324b are on the second sections 380a, 380b attached to fastening devices 382a, 382b. According to one exemplary embodiment, the fastening devices 382a, 382b are designed as lockable bearings in order to effect the angular adjustment of the first sections 374a, 374b. As can be seen in FIG. 4, the second sections 380a, 380b of the guide plates 324a, 324b are arranged to form an input section 384 and an output section 386 of the buffer device 320 together with the base plate 322.

As shown in FIG. 3, according to another exemplary embodiment, the second guide plate 324b of the buffer device 320 can be fastened to the one guide device 336a of the paper delay device.

In the exemplary embodiment shown in FIG. 4, the cover hood 324c is fastened to the second sections 380a, 380b of the guide plates 324a, 324b. This forms an air chamber 388 in which the vibrations occurring at high paper feed speeds during loop formation are damped. The hood 324c is also used for sound absorption.

As in the first exemplary embodiment, the buffer device 320 comprises a sensor device which is formed by a light-emitting element 323a and a light-receiving element 323b. The element 323a is arranged adjacent to the guide plate 324a and emits light in the direction of the guide plate 324b and onto the element 323b arranged thereon. The sensor device 140 determines the height of the loop 370 forming in the buffer device 320.

The behavior of the loop 370 at high paper feed speeds, for example above 0.8 m / s, can be reproduced again by the configuration of the buffer device 320 described above, so that there is no negative influence on the cutting accuracy. The tolerance This ensures that the cutting accuracy is maintained and there are no incorrectly cut sheets of paper.

In the following, reference is again made to FIG. 3. The paper delay device 306 includes a stamp member 328 held in a stamp member receptacle 330. The paper delay device 306 further comprises a counter stamp 332, the paper web 308 being passed between the stamp 328 and the counter stamp 332. The punch 328 is connected to a piston 334 via the punch member receiving device 330. The piston 334 is guided in a guide device 336a, 336b. The piston 334 is biased by a spring 338 such that the spring force is effective to separate the punch 328 from the counter punch 332. The piston is connected to a roller 340 at an end facing away from the stamp. The actuation of the stamp, i.e. its movement against the counter-punch 330 takes place by means of a cam disk or camshaft 342, which is connected to the roller 340. The camshaft 342 includes a first portion 342a which causes the punch 328 to be pressed against the counter punch 332 when the roller 340 is connected to this area 342a. If the roller 340 is located in a second region 342b of the cam plate 342, the stamp 330 is separated from the counter-stamp 332 by the spring force exerted by the spring 338.

In other words, the paper is decelerated while the roller 340 is in the area 342a of the cam 342 and that no deceleration is applied to the paper while the roller 340 is in the area 342b of the cam 342.

A guide device 344 is arranged between the paper delay device 306 and the cutting device 304, which has a drive roller 346 and a guide roller 348, between which the paper web 308 is guided. The guide roller 348 is biased against the drive roller 346 by a spring 350. The transport speed of the guide device 344 is several times higher than the transport speed of the feed device 302. This ensures that the loop that has accumulated during the deceleration process is removed again by the next clamping cycle, the minimum height in the buffer device not being undershot.

In the exemplary embodiment shown in FIG. 3, the cutting device 304 comprises a drop knife 352 which is guided between two guide devices 354, 356. The knife 352 may be in the form of a guillotine knife and is arranged substantially perpendicular to the paper running direction. The paper web 308 to be cut is guided between the knife 352 and a shear bar 358. The cutting machine 300 further comprises a paper discharge device 360, which is arranged downstream of the cutting device 304 in the paper running direction. The paper discharge device 360 comprises a drive roller 362 and a guide roller 364, between which the cut paper is guided. The roller 364 is biased against the drive roller by means of a spring 366. A horizontal guide device 368 is provided in order to ensure secure guidance of the cut paper from the cutting device 304 to the paper discharge device.

It should be noted that the paper discharge device 360 transports the paper at a higher speed than is fed by means of the feed device 302. The speed of the paper guide devices 344, 360 are approximately the same. This ensures that the cut papers are safely removed from the cutting machine 300.

The paper web 308 can, for example, be printed on one or on both sides by a printer device (not shown). The printer setup is located here with respect to the paper running direction in front of the paper feed device 302.

The individual drive elements of the cutting device 300 are controlled by a control device (not shown in FIG. 3), this control device firstly ensuring that the paper web is advanced by the desired cutting length in the feed phase, and then the cutting of the paper web is actuated , On the other hand, the control device ensures that the paper loop that has accumulated in the buffer device does not fall below the minimum height by suitable control of the corresponding drive elements. The sensor device detects a height h of the paper loop 370 (FIG. 4) in the buffer device 320 and outputs a corresponding detection signal to the control. The "height" of the loop is the distance that it extends in a direction that is perpendicular to a plane in which the paper web is fed and cut.

In the exemplary embodiment shown in FIG. 3, the knife 352 arranged in the cutting device 304 is, for example, a falling knife. In the case of using a drop knife, the paper delay device 306 is controlled such that the paper web 308 is completely stopped during the cutting by the action of the stamp 328 on the paper web 308.

According to an embodiment of the present invention, a so-called format recognition device can be arranged in front of the paper feed device with respect to the paper running direction, as is known per se in specialist circles. This format recognition device controls the respective drives of the paper feed device, the paper delay device and the paper cutting device in such a way that the paper web is cut in accordance with the predetermined format. According to a further exemplary embodiment, a detection device can be arranged adjacent to the paper delay device, which detects predetermined markings on the paper web in order to control the paper delay device and the cutting device in such a way that the paper web is cut in accordance with the predetermined format, depending on the detection of this marking.

The detection device arranged adjacent to the delay device can be, for example, an optoelectronic converter which can detect the corresponding markings on the paper web.

According to a further exemplary embodiment, the cutting machine can comprise a cutting device which is designed there as a rotary knife. The rotary knife comprises a roller to which a blade is attached. In one case, the blade can be arranged at a fixed angular position of the roller and, together with the shear bar, by a corresponding shaping of the blade and the shear bar, as is known per se in the art, exert a shearing effect on the paper web to be cut. It is necessary for the paper retarding device to stop the paper web completely during the cutting.

A further embodiment of the rotary knife can be such that the blade is not attached to a fixed angular position of the roller, but instead extends continuously from a first angular position to a second angular position. It is further necessary that the paper retarding device stop the paper web only to determine the position at which the cut is to be made, and then allow the paper web to move further at a speed which is adapted to the rotational speed of the rotary knife so that a cutting edge conforms sets that is perpendicular to the direction of the paper web. The onward transport of the paper web from the paper retarding device to the cutting device is carried out by means of the guide device which ensures that the speed described above is adapted to bring about the straight cut. A difference compared to the feeding speed of the paper web into the cutting machine is compensated for by the buffer provided.

Some performance parameters of a cutting machine, as described for example with reference to FIG. 3, are given below.

The cutting machine 300 described with reference to FIG. 3 has a performance of 24,000 cuts per hour, with dimensions of the resulting format of 304.8 x 210 mm. This corresponds to about 7 cuts per second. The constant paper feed speed in such a cutting machine is 2.03 m / s.

Instead of the knife drives described above, the knife of the cutting device can also be driven by a continuously driven motor with a subsequent switchable 1-speed clutch.

It will be apparent to those skilled in the art that the present invention is not limited to the embodiments described above. In fact, it is also possible to implement the arrangement shown in FIG. 1 with the double element solution known from FIG. 3 with regard to the retarding device of the paper web. Likewise, in the exemplary embodiment shown in FIG. 1, a hood can additionally be provided in the buffer device 104 in order to further improve the damping. Likewise, in the embodiment shown in FIG. 3, a conveying device, as used in the embodiment in FIG. 1, can be used instead of the stamp.

Instead of the sensors described above, other Sensor arrangements familiar to experts are used to record the loop height. It will also be apparent to those skilled in the art that the components used in the examples described above can be replaced as needed.

Claims

claims

1. Device for cutting paper webs with

- a paper feed device (102; 302);

- a cutting device (108; 304);

- A paper delay device (106; 306), which is arranged between the paper feed device (102; 302) and the cutting device (108; 304) and which delays the fed paper web (112; 308) in such a way that on the paper web (112; 308 ) a position is determined at which the cutting device (108; 304) cuts the paper web (112; 308);

- A buffer device (104; 320), which is arranged between the paper feed device (102; 302) and the paper delay device (106; 306), in order to increase an ascending length of the paper web (112; 308) during the delay of the paper web (112; 308). in the form of a loop; and

- a control device (190),

characterized in that

the control device (190) controls the paper feed device (102; 302) and the paper delay device (106; 306) in such a way that the loop (195; 370) accommodated in the buffer device (104; 320) does not fall below a minimum height (h) ,

2. Device according to claim 1, characterized in that that the buffer device (104; 320) has a sensor (140; 323a, 323b) which detects the height (h) of the loop (195; 370) in the buffer device (104; 320), the control device (190) the paper feed device (102; 302) and the paper delay device (106; 306) depending on a detection signal from the sensor (140; 323a, 323b).

3. Device according to claim 1 or 2, characterized in

that the control device (190) controls the paper feed device (102; 302) and the paper delay device (106; 306) in such a way that the loop (195; 370) accommodated in the buffer device (104; 320) does not exceed a maximum height (h).

4. Device according to one of claims 1 to 3, characterized in

that the paper delay device (106; 306) is a paper conveyor device which is arranged between the buffer device (104; 320) and the cutting device (108; 304) and can be actuated to stop or delay the paper web (112; 308).

5. The device according to claim 4, characterized in that the paper conveyor is formed by a pair of drive rollers (160a, 160b).

6. Device according to one of claims 1 to 4, characterized by

a fan device (134; 326a, 326b) which acts on the paper web (112; 308) in the area of the buffer device (104; 320) with an air flow in order to form the loop (195; 370) in the buffer device (104; 320) to support.

7. The device according to claim 6, characterized in that

that the control device (190) controls the fan device (134; 326a, 326b).

8. Device according to one of claims 1 to 7, characterized in

that the paper delay device (306) has a stamp device which acts on the paper web (308).

9. Device according to one of claims 1 to 8, characterized in

that the buffer device (104; 320) comprises a device for guiding (132, 136, 138; 322, 324a, 324b) the accumulated paper web (112; 308).

10. The device according to claim 9, characterized in

that the guide device has a lower guide device (132; 322) in the form of a base plate with respect to the paper feed direction, which has a plurality of recesses (132; 372).

11. The device according to claim 10, characterized in that

that the guide device comprises an upper guide device with a first guide plate (136; 124a) and a second guide plate (138; 124b), each of which has a first section which is arranged at an angle to the paper feed direction (110; 310), and each have a second section which is arranged substantially parallel to the paper feed direction (110; 310), the angle at which the first sections are arranged are adjustable.

12. The device according to one of claims 1 to 11, characterized in that

that the buffer means (320) comprises means for damping vibrations of the accumulated paper web (112; 308).

13. The apparatus according to claim 12, characterized in

that the damping device is formed by a hood (324c) which surrounds the guide device (322, 324a, 324b) and forms an air chamber.

14. The device according to one of claims 1 to 13, characterized in that

that the cutter (108; 304) is a drop knife that is substantially perpendicular to the one to be cut

Paper web (112; 308) is arranged, or comprises a rotary knife.

15. The apparatus according to claim 14, characterized in

that the paper delay device (106; 306) stops the paper web (112; 308) completely.

16. The device according to one of claims 1 to 15, characterized in that

that the paper web (308) is provided with guide perforations; and

that the paper feed device (302) comprises a tractor device (318a) for guiding the paper web (308).

17. The device according to one of claims 1 to 16, characterized by

a printer device, which is arranged in front of the paper feed device (102; 302) with respect to the paper travel direction, for printing on the paper web (112; 308).

18. Device according to one of claims 1 to 17, characterized by

a paper discharge device (360), which is arranged behind the cutting device (304) with respect to the paper running direction, in order to forward the cut individual papers in each case.

19. The apparatus according to claim 18, characterized in

that the paper discharge device (360) discharges the cut individual papers at a higher speed than the speed at which the paper feed device (302) feeds the paper web (308).

20. Device according to one of claims 1 to 19, characterized in that

that a format recognition device is arranged in front of the paper feed device (102; 302) with respect to the paper running direction, which controls the respective drives of the paper feed device (102; 302), the paper delay device (106; 306) and the cutting device (108; 304) in this way that the cutting of the paper web (112; 308) is carried out according to a predetermined format.

21. Device according to one of claims 1 to 19, characterized in that that a detection device is arranged adjacent to the paper delay device (106; 306), which detects predetermined markings on the paper web (112; 308) in order to, depending on the detection of these markings, the paper delay device (106; 306) and the cutting device (108; 304) to be controlled in such a way that the cutting of the paper web (112; 308) takes place in accordance with a predetermined format.

22. The apparatus according to claim 21, characterized in

that the detection device detects an optoelectronic device.