EP2331305B1

EP2331305B1 - Device for transversal perforation, at high speed, of a paper web

Info

Publication number: EP2331305B1
Application number: EP09774700.0A
Authority: EP
Inventors: Quirino Fausto Sestini
Original assignee: Hunkeler AG
Current assignee: Hunkeler AG
Priority date: 2008-08-12
Filing date: 2009-08-12
Publication date: 2016-09-07
Anticipated expiration: 2029-08-12
Also published as: WO2010018449A2; EP2331305A2; WO2010018449A3; ITPI20080075A1; IT1397637B1

Description

Field of the invention

The present invention relates to the field of printing and, in particular, it relates to a device for transversal perforation, at high speed, of a paper web in paper converting and/or printing systems.
This way, the perforated paper according to predetermined score lines can be easily torn, by the user, into smaller sheets, for example for tearing off a paying-in slip, an invoice or another document.

Description of the technical problem

The presently known paper perforation devices in paper converting and/or printing machines that use a continuous paper web normally use a cutting tool, for example a toothed blade disc, to perforate the web while in movement.
In particular, as described in EP0646468 , a device is known for transversal perforation that operate in a discontinuous way that allows, furthermore, adjusting the perforated portion size and position.
However, the high efficiency of the presently known printers that can operate with a very high working speed, at which controls are much more difficult.
In particular, a first drawback arises of the presently known perforation or cutting devices, which normally operate at a relatively low working speed, to cope with the high printing speed in the printers.
In EP0646468 the perforation of the paper is made by a perforation tool that is mounted on a driven support that achieves a linear speed that is substantially identical to the counter-support roller only in the perforation steps, decelerating or accelerating in the other steps when cutting does not occur; this functionality can be adjusted according to the needs of the producer and of the paper format.
The main drawback of such a device is a high moment of inertia of the cutting tool. In particular, when the perforation tool is caused to rotate at a high speed, it cannot achieve quickly the desired speed owing to the high moment of inertia.
In US 2007/000364 and WO9812027A1 a perforation device is described that comprises a first and a second rollers that are arranged parallel with respect to each other and a countersupport roller that is coupled to the first roller and a blade that is coupled to the second roller-having one or more protrusions for cutting or perforating in a discontinuous way a flow of paper that crosses the two rollers. The rollers are controlled in order to have a variable cutting speed and approaching speed.
These devices are not adapted however to treat very large paper webs that are printed as two parallel flows of documents. In this case, a transversal perforation may not be necessary on two documents that are adjacent to each other, and can be required on only one of them. In this case the existing machines, cannot meet this production need.

Summary of the invention

It is a general object of the present invention to provide a device for transversal perforation at high speed of a paper web, which is modular and flexible in the many types of perforation that may be required in order to make, starting from a standard paper size, a plurality of different formats.
It is a further feature of the present invention to provide a device for transversal perforation at high speed, of a paper web that carries out a transversal perforation of documents, in a selective way on the right and/or left side of a paper document.
It is finally a feature of the present invention to provide a device for transversal perforation at high speed of a paper web that is structurally easy and reliable in its operation.
These and other objects are achieved by a device according to claim 1 for transversal perforation, at high speed, of a flow of paper, in particular paper documents, comprising:

a first and a second roller, each roller having an own rotation axis and two side faces, said rollers arranged transversally with respect to said flow of paper and arranged with two respective side faces opposite to each other and facing each other, each of said rollers having a plurality of cutting blades that are parallel to said axis, said cutting blades adapted to provide a transversal cut on said flow of paper;
an actuating means for operating independently said first and second roller;
a drive drive means said actuating means in order to actuate each of said rollers at least at a linear cutting speed and a linear approaching speed, wherein said linear cutting speed is substantially identical to the speed of said flow of paper and to that of a counter-support on which said paper runs, in order to make on said flow of paper a transversal cut, and wherein said linear approaching speed is different from that of said flow of paper in order to carry out an approaching movement to prepare making a following transversal cut when reaching again said linear cutting speed.

The first and second rollers that house multiple cutting blades allow to limit the rotation angle for making a cutting cycle.
Preferably, said cutting blades are arranged at 120° from each other. This way, the tool operating time and the overall duration of the cutting blades are reduced since they carry out each a third of the perforation.
Advantageously, said first and second rollers are coaxial to each other.
Preferably, said first and second rollers are equal to each other and have, in particular the same diameter.
Advantageously, said first and second rollers are mounted pivotally on a single shaft and turn independently from each other about said shaft.
Advantageously, said first and second rollers have a determined shape for which is minimum the moment of inertia, in order to oppose minimum resistance and show maximum agility to variation of linear speed of rotation achieved during the operation.
Preferably, said actuating means provide an independent external motor for each roller, that is adapted to provide, through transmission means, said linear speed of rotation and said approaching movement.
Advantageously, said cutting blades are put in a releasable way in said rollers in order to be replaced or adjusted according to the kind of cut to carry out.
Preferably, said perforation device comprises, furthermore, a plurality of cutting elements that perform, on said flow of paper, longitudinal cuts that are independent from said transversal cuts.

Brief description of the drawings

The invention will be made clearer with the following description of an exemplary embodiment thereof, exemplifying but not limitative, with reference to the attached drawings in which:

figure 1 shows the device for transversal perforation, at high speed, of a paper web, according to the invention;
figure 2 shows a view particular of the rollers with its perforating blades, of Fig. 1, according to the invention;
figure 3 shows a cross sectional view of the rollers, of Fig. 2, and depicts, furthermore, the rotating shaft and the thrust bearings that allow its correct rotation;
figures 4 and 5 show respectively a diagrammatical view and a time diagram that reproduces the succession of the various approaching, perforation and releasing steps of the cutting rollers on the flow of paper.

Description of a preferred embodiment

With reference to Fig. 1, a perforating device 1 is shown, for perforating at high speed a paper flow 16. It mainly comprises a first and a second roller 4 and 4' that are adjacent to each other. In particular, each roller has an own rotation axis 15 and two side faces 4a/4b and 4a'/4b', and is arranged transversally with respect to paper flow 16 so that two side faces 4a/4a' are opposite to each other and face each other (Fig.2).
Furthermore, rollers 4 and 4' have each a plurality of cutting blades 14 and 14' (as shown in Fig. 2) parallel to axis 15. Cutting blades 14 and 14' are adapted to provide a transversal cut on paper flow 16 that runs, at high speed, on a counter-support roller 3.
Rollers 4 and 4' are operated independently from motors 8 and 8', which make up the actuating means. In particular, the movement of the motors is transmitted by means of pulleys 5 and 5' that are mounted outside and coaxially to rotation axis 15 and integral to rollers 4 and 4'. Through further pulleys 7 and 7', and belts 6 and 6', motors 8 and 8' transmit independently to the respective roller 4, 4' a rotational cutting movement and a rotational approaching movement, by dedicated control means (not shown in the figures).
More precisely, the control means for operating motors 8 and 8' are adapted to operate at a linear cutting speed or at a linear approaching speed the respective rollers 4 and 4', where the linear cutting speed is substantially identical to paper flow 16 and to that of counter-support 3, on which the paper runs, in order to make on paper flow 16 a transversal cut. Vice-versa, the linear approaching speed is different from that of paper flow 16 in order to carry out an approaching movement to eventually make a following transversal cut when reaching again the linear cutting speed.
The movement of- paper flow 16 is caused, -in device 1, through counter-support 3 which is brought into rotation through an outer motor 9. In this case, the motion transmission is carried out by a first pulley 12, that is integral to roller 3, and a second pulley 10, that is integral to motor 9, both united by a belt 11 that carries out the active connection and allows the transmission of the motion.
According to a preferred exemplary embodiment, belt 11 is a conical teeth belt such that the movement is transmitted without any sliding between the belt and the pulley 12.
Figure 1 shows, also, rollers 13a and 13b that are adapted to direct paper flow 16 entering and exiting the machine in optimal conditions for carrying out the perforation.
Furthermore, always as shown in Fig. 1, perforating device 1 provides a plurality of cutting elements 10 that perform, on paper flow 16, longitudinal cuts that are independent from the transversal cuts.
Figure 2 shows, in an enlarged view of device 1, rollers 4 and 4', coaxial to each other, mounted on the rotating shaft 15 that, according to the invention, rotate independently from each other about axis 15, by motors 8 and 8' as described above.
In particular, in the present exemplary embodiment, first roller 4 and second roller 4' are equal to each other and have a same outer diameter. Furthermore, they have a determined shape, substantially with triangular cross section, for which the moment of inertia is minimum, in order to oppose minimum resistance and show maximum agility to a variation of linear speed of rotation achieved during the operation.
In addition, rollers 4 and 4' comprise multiple cutting blades 14 and 14', which are arranged in a releasable way in the rollers in order to be replaced or adjusted according to the kind of cut to carry out.
In particular, cutting blades 14 and 14' are arranged at 120° C from each other in order to improve the tool operating time and the overall duration of the cutting blades, each carrying out one third of the perforations. Moreover, first roller 4 and second roller 4' by having multiple cutting blades allow, furthermore, to limit the rotation angle for making a cutting cycle.
Fig. 3 shows in detail two rollers 4 and 4' of Fig. 2, cross sectioned along a generatrix. The cross section view shows the roller bearings that allow adjusting the precise rotation about shaft 15. In fact, conical roller bearings 16 and 17 are designed for bearing combined radial-axial loads. Furthermore, they are mounted in opposition to each other in order to balance the axial load that acts in an opposite direction.
With reference to Figs. 4 and 5 a time diagram is shown of the approaching and perforation steps of a roller 4 or 4' on paper flow 16. In particular, at a time T0 paper flow 16, which slides on counter-support 3, is at running speed, whereas perforation rollers 4 or 4' are still. At a time T1 roller 4 or 4' is operated and accelerates up to a cutting speed that is substantially identical to counter-support 3 at a time T2. Then, in the successive steps there is an approaching movement according to which roller 4 or 4' is approached to paper flow 16 and carries out the perforation at a time T4 perfectly in phase with the linear speed of the documents and with a predetermined perforation position. This way, transversal perforation are made that are of optimum quality.
The successive step is deceleration, according to which between a time T5 and T6 either roller 4 or 4' stops or prepares itself to a new perforation step as above described.
In particular, the device is adapted to carry out the perforation at a minimum distance of four inches with respect to each other at maximum speed. This distance is function, in any case, of the running speed of paper flow 16.
The foregoing description of a specific embodiment will so fully reveal the invention according to the conceptual point of view, so that others, by applying current knowledge, will be able to modify and/or adapt for various applications such an embodiment without further research and without parting from the invention, and it is therefore to be understood that such adaptations and modifications will have to be considered as equivalent to the specific embodiment. The means and the materials to realise the different functions described herein could have a different nature without, for this reason, departing from the field of the invention. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

Claims

A device for transversal perforation (1), at high speed, of a flow of paper comprising:
- a first and a second roller (4,4'), each roller (4,4') having two side faces (4a/4b,4a'/4b'), said rollers (4,4') mounted pivotally on a single shaft (15) and turning independently from each other about said shaft (15), said rollers (4,4') arranged transversally with respect to said flow (16) of paper and arranged with two respective side faces (4a/4a') opposite to each other and facing each other, each of said rollers (4,4') having a plurality of cutting blades (14,14') that are parallel to said shaft (15), said cutting blades (14,14') adapted to provide a transversal cut on said flow of paper (16);

- an actuating means (8,8') for operating independently said first and second roller (4,4');

- a drive means for driving said actuating means in order to actuate each of said rollers (4,4') at least at a linear cutting speed and a linear approaching speed, wherein said linear cutting speed is substantially identical to the speed of said flow of paper (16) and to that of a counter-support (3) on which said paper runs, in order to make on said flow of paper (16) a transversal cut, and wherein said linear approaching speed is different from that of said flow of paper (16) in order to carry out an approaching movement to prepare a following transversal cut when returning to said linear cutting speed.
A device, according to claim 1, wherein said cutting blades (14,14') are arranged at 120° from each other.
A device, according to claim 1, wherein said first and second rollers (4,4') have a same diameter.
A device, according to claim 1, wherein said first and second rollers (4,4') have a triangular cross section.
A device, according to claim 1, wherein said actuating means (8,8') comprise an independent external motor for each roller (4,4') adapted to provide, through transmission means (5,5',7,7',6,6'), said linear speed of rotation and said approaching movement.
A device, according to claim 1, wherein said cutting blades (14,14') are mounted in a releasable way.
A device, according to claim 1, comprising a plurality of longitudinal cutting elements (10) that perform, on said flow of paper (16), longitudinal cuts that are independent from said transversal cuts.