DE112016003097T5 - Method for grooving and cutting sheet materials - Google Patents

Abstract

A pre-printed sheet (12) is caused to advance along a predetermined path passing through one or two creasing machines (30, 60) which successively apply two arrays of straight grooves (17, 18) on the sheet and a grid of score lines in two generate vertical directions. The score lines are applied at predetermined intervals with respect to datum points (16) disposed on the signature, for example, datum marks printed on a surface of the signature. The fiducial points are detected by optical devices (50) operatively connected to corresponding alignment devices (40) which correctly align the sheets during transport to the creasing machines. Finally, a cutting machine (90) cuts the edges or other parts of the sheet (12) using reference points already used to form the score lines. In this way, the cuts are made with respect to the score lines with absolute accuracy.

Description

Technical field

This invention relates to the processing of sheets of cardboard, paper and similar materials. In particular, the invention relates to the creasing and cutting of sheets and board into complex shapes.

State of the art

Grooving and cutting is mainly done using automatic presses known as slicers. These machines use a flat punch that includes one or more blades or that has a cutting profile that reflects a particular shape. Non-cutting blades, known as knives, which cause localized crushing of the carton so that it can subsequently be folded along certain lines can also be used in the punch.

A punch of the above type has a high production rate with identical cuts, but is associated with high costs. In the carton technology sector, the advent of digital press has significantly increased the need to press small quantities in each production run. It is therefore appropriate to forego high processing speed and pay more attention to greater machine flexibility to rapidly change production from one format to another. It is also desirable to eliminate the cost of the punch; indeed, the cost of the punch in small runs has a significant impact on the cost of pressing a single sheet.

The grooves obtained by using a punch inevitably cause a two-dimensional or diagonal shortening of the sheet, which is uncontrollable and difficult to accurately calculate in advance. The diagonal deformation of the sheet has the consequence that the subsequent cutting of the sheet after the groove is not performed with high accuracy with respect to the score lines.

Recently, digital cutting and creasing machines with laser technology have appeared on the market. These machines have produced carton technology products in particularly complex and personalized forms in short runs, such as cartons or interior cut-out labels. The grooves obtained using laser technology are created by firing a groove in a surface of the sheet, thereby creating weak spots in the sheet that may be undesirable. In addition, laser technology is effective in creating grooves in relatively thin paperboard sheets, but does not provide optimal results over a particular paperboard weight.

Creasing machines are also known which comprise a pair of counter-rotating cylinders having respective mating male / female rills of polymerizable material through which the individual sheets to be corrugated are passed. The grooves obtained with such rotating cylinder machines suffer distortions in a "diagonal" direction, that is, they have both a longitudinal and a transverse component. In addition, these machines have a dead time which must be eliminated or at least reduced to allow the scoring punch to polymerize.

Finally, stack grooving and rotary grooving machines are known which produce straight grooves quickly and economically.

The US 2011/0152048 A1 sets open the formation of vertical score lines obtained by passing sheets sequentially through two consecutive score stations. A second creasing machine outputs one or more creasing lines aligned perpendicular to an array of creasing lines previously transferred to the same sheet by a first creasing machine. The US 2005/0209075 A1 discloses a method for processing carton blanks in which reference marks on the blanks are optically detected to provide creasing and cutting lines with accuracy.

Summary of the invention

A first object of this invention is to provide grooves in sheet materials which can then be subjected to a subsequent cutting operation which is performed precisely with respect to the grooves.

Another object of this invention is to perform scoring operations quickly and economically. It is also desirable that creasing be done flexibly, that is with the ability to quickly switch to the production of various formats.

These and other objects and advantages, which will be better understood hereinafter, are achieved according to one aspect of the invention by a method as defined in the appended claims.

In summary, a pre-printed sheet is caused to advance along a predetermined path, passing through one or two creasing machines which successively transfer two sets of straight grooves onto the sheet, thereby producing a pattern of score lines in two perpendicular directions. The score lines are arranged at predetermined intervals with respect to reference points disposed on the sheet, for example, reference points along their edges and reference marks printed on a surface of the sheets. The fiducial marks are detected by optical devices operatively connected to corresponding alignment devices. The alignment devices correctly align the sheets as they move toward the creasing machines. Finally, a laser machine cuts the edges or other parts of the sheet using reference points that have already been used to form the score lines as reference points. In this way, the cuts are made with respect to the score lines with absolute accuracy.

Brief description of the drawings

Some preferred but non-limiting embodiments of a method according to the invention will now be described. Reference is made to the accompanying drawings, in which:

1 and 2 Fig. 15 is perspective views schematically illustrating a first embodiment of a method of processing sheet materials;

3 Figure 3 is a schematic perspective view of some elements that may be used as sheet aligning devices in some embodiments of the method;

4 and 5 are schematic side views of the components in 3 represented at two consecutive times;

6 Fig. 12 is a perspective view schematically illustrating a second embodiment of a method for processing sheet materials;

7 and 8th Figs. 3 are perspective views schematically illustrating a third embodiment of the method;

9 Fig. 12 is a schematic perspective view illustrating a sheet of material having grooves and fiducials for forming the same;

10 and 11 are schematic side views of two successive stages of work, in which grooves in an arc of the in 9 generated type are generated; and

12 and 13 Fig. 15 are perspective views schematically illustrating a fourth embodiment of the method.

Detailed description

Referring first to the 1 and 2 Here are some of the components of a set of machines for creasing and cutting sheet materials. A first creasing machine 30 , a second creasing machine 60 and a processing machine 90 for cutting sheets are shown schematically one after the other.

Preferably, the processing machine 90 (or sheet cutting machine) a laser processing machine. The choice of using a laser machine to cut the sheets is an advantage, but should not be construed as limiting the implementation of this method.

The two creasing machines provide a first array of parallel grooves in a given direction and a second array of grooves perpendicular to that given direction, each on a sheet, thereby creating a grid of arcuate lines according to a predetermined pattern. After grooving, the laser processing machine cuts complex shapes around the sheet and optionally cuts within the sheet and / or groove in directions different from those of the groove made by the two grooving machines.

This method is not limited to paper and paperboard use, but may also find a useful application in the processing of sheets of other materials such as leather, fabrics, rubbers, plastics, etc.

The creasing machines 30 . 60 and the cutting machine 90 together determine a path for advancing the bows 12 , The web begins at an upstream station where a sheet feeder 11 is provided, each having a bow 12 from the top of a pile 13 the pre-printed sheets of cardboard or cardboard, and transfers the bow to a conveyor system 21 . 22 . 25 . 26 , The conveyor system is used to feed the sheets one at a time from the sheet feeder 11 to transport to a terminal where the processing machine 90 located.

In accordance with the in the 1 and 2 In the embodiment shown, the conveyor system defines an L-shaped path for the sheets in which a first straight section extending in a first direction A is followed by a second straight section extending in a second direction B perpendicular to the first direction.

Every bow 12 has an entry edge 14 and an upper surface or an upper surface 15 on which marks, schematically represented by 16 or other fiducial marks, can be printed. These fiducials may be used to determine the exact position and orientation of the sheet so that grooves and subsequent cutting can be made as discussed above. The term "entry", which is used here to the edge 14 to define refers to the first direction A, in which the arcs advance. Terms such as "longitudinal" or "transverse" are interpreted with reference to the instantaneous direction of advancement of the sheet.

In the embodiment of the 1 and 2 there is shown a belt conveyor system comprising a plurality of successive parallel motor driven belts. Alternatively, a roller conveyor system may be used which provides a plurality of motor driven rubber coated rollers or a mixed conveyor system with rollers and belts. The illustrated conveyor system comprises a first set 21 motor driven parallel belts extending in the first direction A and circulating in transversely spaced parallel planes. The first set of conveyor belts each take a bow 12 from the sheet feeder 11 on and causes it in the first direction A towards the first creasing machine 30 advances on each incoming sheet 12 a first array or plurality of straight, parallel grooves 17 ( 2 ) transmits. The crease lines 17 in the first arrangement, A is spaced from each other in the first direction and extends parallel to the leading edge 14 of the bow.

The creasing machine 30 in the illustrated embodiment, a per se known Stapelrillmaschine that is a straight blade 31 which extends perpendicular to the first direction and by a linear activator 32 is operated vertically. The blade 31 acts with a lower counterblade 33 together, which has an upright straight groove 34 which extends perpendicular to the first direction. A roll grower known per se (not shown) may be used as an alternative to a stack grower.

Immediately the creasing machine 30 upstream there is an alignment 40 that serves to the at the grooving machine 30 incoming bows 12 to align with respect to a predetermined direction. The alignment device causes the sheet to rotate in a horizontal plane, if necessary, by an angle determined individually for each sheet, so that the sheet is exactly in relation to the creasing machine 30 can be aligned.

The alignment device 40 includes two motorized rollers 41 . 42 , which can be operated independently of each other and which are spaced in a transverse direction with respect to the first direction. The motorized rollers 41 . 42 can each rotate with respect to two parallel or coincident axes that are transverse to the first direction of advance. The two motorized rollers are configured to rest on a surface of the arches 12 (in this embodiment, the lower surface, not shown) roll in the direction of the creasing machine 30 advance.

Each of the two motorized rollers 41 . 42 acts with a corresponding support role 43 . 44 together, which is mounted so that it moves vertically and elastically to the corresponding motor-driven role. The two support rollers 43 . 44 should be on the upper surface 15 the arches 12 Roll off in the direction of the creasing machine 30 Advance to the continuous sheets in contact with the two motor-driven rollers 41 . 42 before the sheets reach the creasing machine.

The motorized rollers 41 . 42 are each from a corresponding electric motor 47 . 48 , preferably a stepper motor, rotationally controlled. Each electric motor can be individually controlled and driven in a different manner than the electric motor that drives the other motorized rollers so as to have different advances between two laterally spaced zones on the same arc 12 to generate and therefore to turn the arc by a desired angle in the horizontal plane.

Different control of the two electric motors may be effected in various ways to produce a desired rotation of a sheet. For example, each electric motor may be suitably stopped or driven with respect to the other electric motor. In one possible embodiment, the rotation of the sheet in the horizontal plane may be effected by stopping one of the two electric motors, and therefore one of the motorized rollers, while the other electric motor continues to rotate through a certain angle. In this way, the bow is held on one side, while it is still advanced on the opposite side by a certain distance. As one Alternatively, the direction of rotation of one of the two motors may be reversed to cause a portion of the sheet to move backward while holding the opposite side of the sheet stopped (stopping the motor and the corresponding rollers) or advancing in a controlled manner. In another embodiment, one of the two electric motors may be slowed or accelerated with respect to the other electric motor in such a manner that two laterally spaced portions of the same arc are advanced (or moved backwards) in different ways, with consequent rotation of the sheet at a certain angle.

The support rollers 43 . 44 may be idler rollers or independently motor-driven rollers or rollers, which are rotated by the corresponding motor-driven roller or by means of a gear, such as a gear transmission, in rotation.

According to the in the 1 and 2 In the illustrated embodiment detection means may be provided which are capable of detecting the advancement of a sheet in two transversely spaced positions on the sheet.

In the embodiment in FIG 1 and 2 will be two encoders 49 . 59 with corresponding wheels 45 . 46 used in contact with the sheet as means for detecting the advancing. The two encoders are preferably adjacent to each motor driven roller 41 . 42 and more preferably immediately upstream thereof.

Immediately the creasing machine 30 upstream is an optical detection device 50 provided to the angular orientation of the in the creasing machine 30 incoming bow 12 in a horizontal plane.

According to one embodiment, the optical detection device comprises 50 two photocells (or other equivalent photodetectors), one 51 on the right and one 52 on the left side, which are transversely spaced with respect to the first forward direction. As an alternative optical detection device 50 can you include a TV camera or a photo camera.

• – die Positionen von zwei jeweiligen in Querrichtung beabstandeten Punkten an der Eintrittskante 14 des Bogens 12 auf der Bahn zur Rillmaschine 30 zu erfassen; oder
• – die Positionen von zwei quer beabstandeten Bezugsmarkierungen 16a, 16b auf dem Bogen 12 zu erfassen.

The two photocells 51 . 52 are used to

• The positions of two respective transversely spaced points at the leading edge 14 of the bow 12 on the track to the creasing machine 30 capture; or
• The positions of two transversely spaced fiducials 16a . 16b on the bow 12 capture.

The two reference marks 16a and 16b are spaced sufficiently apart to allow the orientation of the sheet to be checked. In other words, they are spaced sufficiently far apart to allow it to check for the leading edge 14 the arc perpendicular to the forward direction A of the sheet to the first creasing machine 30 is.

In the examples shown here are the reference marks 16 on the upward surface 15 imprinted, and the optical detection device 50 is located above the path of the arches. As an alternative, reference marks 16 be printed on the underside of the sheets, and the optical detection device may be arranged below the path of the sheets.

• – Signale zu empfangen, die die Positionen von zwei in Querrichtung beabstandeten Punkten entlang der Eintrittskante 14 eines Bogens oder zwei Bezugsmarkierungen 16a, 16b auf dem Bogen 12 durch die optische Erfassungsvorrichtung 50 anzeigen;
• – die von der optischen Erfassungseinrichtung 50 empfangenen Signale zu verarbeiten und eine Dateneinheit zu erzeugen, die die augenblickliche Winkelausrichtung des Bogens 12 bezüglich einer vorgegebenen Richtung, beispielsweise bezüglich der ersten Richtung A, angibt;
• – basierend auf den Winkelausrichtungsdaten, ein entsprechendes signalkorrigierendes unterschiedliches Vorrücken zu erzeugen, um ein unterschiedliches Vorrücken zwischen zwei in Querrichtung beabstandeten Zonen desselben Bogens 12 zu erzeugen und somit den Bogen um einen gewünschten Winkel in der horizontalen Ebene zu drehen;
• – das Korrektursignal an mindestens einen der Motoren 47, 48 zu senden, um die Drehung mindestens einer der beiden motorbetriebenen Rollen 41, 42 zu steuern und folglich ein unterschiedliches Vorrücken zwischen zwei in Querrichtung beabstandeten Zonen in dem gleichen Bogen 12 zu erzeugen und daher den Bogen um einen gewünschten Winkel zu drehen, was eine Drehung des Bogens 12 in der horizontalen Ebene bewirkt, um die zwei Punkte an der Eintrittskante oder den zwei Bezugsmarkierungen senkrecht zu der vorher erwähnten gegebenen Richtung A auszurichten, das heißt parallel zu dem Bogen der ersten Rillmaschine 30;
• – Vorrücksignale von den Encodern 45, 46 zu erhalten, um das Vorrücken des Bogens 12 in zwei in Querrichtung beabstandeten Positionen auf dem Bogen zu erfassen; und
• – anhand der von Encodern 45, 46 erzeugten Vorrücksignale zu überprüfen, dass auf dem Bogen zwischen zwei in Querrichtung voneinander beabstandeten Zonen auf dem gleichen Bogen 12 entsprechend dem Korrektursignal tatsächlich ein unterschiedliches Vorrücken übertragen wurde.

Rotary movements of the two motor-driven rollers 41 . 42 are controlled by commands from an electronic processing unit (not shown) to the motors 47 . 48 typically a PLC or programmable logic controller or PC (personal computer) which monitors the operation of all other motor / drive components described herein. In particular, the electronic control and processing unit is provided for this purpose

• Receive signals representing the positions of two transversely spaced points along the leading edge 14 one sheet or two reference marks 16a . 16b on the bow 12 through the optical detection device 50 Show;
• - that of the optical detection device 50 to process received signals and to generate a data unit representing the instantaneous angular orientation of the sheet 12 with respect to a given direction, for example with respect to the first direction A;
• Based on the angular orientation data, to generate a corresponding signal correcting differential advancement to provide differential advancement between two laterally spaced zones of the same arc 12 to generate and thus to turn the sheet by a desired angle in the horizontal plane;
• - The correction signal to at least one of the motors 47 . 48 to send to the rotation of at least one of the two motorized rollers 41 . 42 and thus a differential advancement between two transversely spaced zones in the same arc 12 to generate and therefore to turn the bow by a desired angle, which is a rotation of the bow 12 in the horizontal plane causes the two points at the leading edge or the two fiducials perpendicular to the aforementioned given direction A to align, that is parallel to the arc of the first creasing machine 30 ;
• - Advance signals from the encoders 45 . 46 to get to the advancement of the bow 12 in two transversely spaced positions on the sheet; and
• - on the basis of encoders 45 . 46 generated advance signals to verify that on the arc between two transversely spaced zones on the same arc 12 In fact, a different advance was transmitted according to the correction signal.

As in the 3 . 4 and 5 shown eliminates the system, with the addition of an encoder and its wheel 45 , Settings and corresponding losses, while always ensuring that the of the bow 12 covered distance is monitored independently of all geometric and consistency variables between the various bends. The roles 41 . 43 , which form part of the same support roller pair, are biased upwards with a fixed pressure which is suitable for advancing the sheets. The wheel 45 the encoder becomes elastic against the bow 12 pressed with a fixed minimum pressure that is sufficient to the wheel 45 not to slip when the bow 12 advances. If the bow 12 Has thickness variations that in 5 schematically as 12a are shown, these cause a change in the radii R and R1 of the roles 41 . 43 or slippage between these two roles. The wheel 45 of the encoder is not affected by such thickness variations and therefore determines the exact distance that the arc 12 travels and sends via the corresponding encoder 49 the distance data to the processor (PLC). The latter compares the measured distance data with predetermined theoretical data and varies the rotational speed of the rotor 47 that with the resolver 58 connected is. As a result, the roles are running 41 and 43 with a variable controlled motion, whereby the movement of the sheets, which differ from each other, remains the same regardless of the presence of any local variations in thickness.

A monitoring unit in the 3 to 5 can also be used in a technical context other than the method described herein, for example to adjust the orientation of a web of material that must undergo some form of processing of carding technology and therefore not necessarily to create a pattern of vertical grooves. The monitoring unit serves to induce differential advancement between two laterally spaced zones of the same sheet as it advances in a conveyor system, and therefore to effect rotation of the sheet by a desired angle in the horizontal plane. According to one embodiment, the unit comprises:
two motorized wheels 41 . 42 rotating with respect to two parallel or coincident axes which are transverse to the direction in which the sheets are advanced and spaced apart in a transverse direction; two electric motors that can be independently controlled to rotate the respective motor-driven rollers; and preferably
For each motor-driven roller a corresponding encoder 49 . 59 which rotates as a wheel rotating with a wheel that can roll on the arches in positions aligned longitudinally with the motorized rollers.

The reference number 22 denotes a second plurality of motor-driven parallel belts extending in the first direction A and extending in transversely spaced parallel planes. The second set of conveyor belts takes individual bows 12 on top of that, the creasing machine 30 have passed through and causes them in the first direction A to a straight stop edge 23 move. The edge 23 extends perpendicular to the first direction A and parallel to the second direction B, in which the arcs 12 after reaching the edge 23 to get distracted.

The edge 23 is located in the station between the two creasing machines, where the bow 12 undergoes a distraction of the movement.

digit 53 denotes another functional photodetecting device, in this embodiment a television camera or a photographic camera. The photodetector 53 may be located above the track followed by the sheets to their angular orientation upstream of the first creasing machine 30 capture. The photodetector 53 performs a quality check, verifying that the grooves created were actually made according to the design requirements, and transmits position or angular registration data for the sheets 12 to the electronic unit.

Adjacent to the edge 23 there is a push element 24 that extends in the second direction B to those on the edge 23 of the second set of bands 22 adjacent arches to a third set of parallel motor-driven belts 25 to move.

The bands 25 extend in the second direction B. The bands 25 each take a bow 12 from the pusher 24 on and cause it in the second direction B in the direction of the second creasing machine 60 advancing a second array of straight parallel grooves 18 on every Bow leaves ( 2 ). The grooves 18 in the second arrangement are spaced in the second direction B and extend perpendicular to the grooves 17 the first arrangement, previously through the first creasing machine 30 were transferred.

The second creasing machine 60 In the illustrated embodiment, a stack grooving machine is similar to the first grooving machine 30 that with a straight blade 61 is provided, which extends perpendicular to this and a linear drive 62 is driven vertically. The blade 61 works with the lower counterblade 63 together, the one straight up-facing groove 64 which extends perpendicular to the second direction. A rotary creasing machine can be used as an alternative to the stacking machine 60 be used.

Similar to the first creasing machine 30 upstream in turn from the second creasing machine 60 an alignment device 70 provided upstream, the individual at the second creasing machine 60 incoming bows 12 so that, if necessary, it rotates at an angle determined on an individual basis for each sheet to be precise with respect to the second creasing machine 60 align.

The alignment device 70 includes two motorized rollers 71 . 72 which are operated independently of each other and spaced in a transverse direction with respect to the second direction B. The motorized rollers 71 . 72 can each rotate with respect to two parallel or coincident axes, which extend transversely to the second direction of advance B. The two motorized wheels 71 . 72 are configured to rotate on the underside of the arches that face the second creasing machine 60 advance.

Each of the two motorized rollers 71 . 72 acts with a corresponding support role 73 . 74 together, which is mounted so that it is vertically movable and elastically loaded to the corresponding motor-driven role out. The two support rollers 73 . 74 should be on the upper surface of the arches 12 roll off in the direction of the second creasing machine 60 Advance to the sheets during transport in contact with the two motorized rollers 71 . 72 to keep.

The motorized rollers 71 . 72 are each by a corresponding electric motor 77 . 78 , preferably a stepper motor, in the same way as above for the motorized rollers 41 . 42 described, set in rotation. Every electric motor 77 . 78 can be controlled individually and operated differently than the electric motor that drives the other motor-driven roller to a different advancement between two transversely spaced zones of the same arc 12 to generate and therefore to turn the arc by a desired angle in the horizontal plane.

sensing devices 75 . 76 which are capable of detecting the advance of a sheet at two transversely spaced positions on the sheet itself are provided. Preferably, these advance detection devices use two encoders 75 . 76 with wheels in contact with the bow. The two encoders are preferably adjacent to each motorized roller 71 . 72 and more preferably immediately upstream thereof.

Immediately the groove machine 60 upstream there is an optical detection device 80 for detecting the angular orientation of the in the creasing machine 60 incoming bow 12 in a horizontal plane.

• – Erfassen der Positionen von jeweils zwei in Querrichtung beabstandeten Punkten an einer (seitlichen) Kante 19 des Bogens 12, die an der Rillmaschine 60 ankommt; oder
• – Erfassen der Positionen von zwei Bezugsmarkierungen 16c, 16d, die in Querrichtung auf dem Bogen 12 beabstandet sind.

According to an embodiment, the optical detection device 80 two photocells (or other equivalent photodetectors) comprise one 81 on the right and one 82 on the left side, which are transversely spaced with respect to the second advancing direction. As an alternative optical detection device 80 can you include a TV camera or a photo camera. The optical detection device 80 is used for

• Detecting the positions of each two transversely spaced points on a (lateral) edge 19 of the bow 12 at the creasing machine 60 arrives; or
• - Detecting the positions of two reference marks 16c . 16d running in the transverse direction on the arch 12 are spaced.

• – erfasst die elektronische Verarbeitungseinheit Signale von der optischen Erfassungsvorrichtung 80, die die Positionen von zwei in Querrichtung beabstandeten Punkten entlang einer Seitenkante 19 des Bogens oder zwei Bezugsmarkierungen 16c, 16d auf dem Bogen 12 anzeigen;
• – verarbeitet die elektronische Verarbeitungseinheit die von der optischen Erfassungsvorrichtung 80 empfangenen Signale und erzeugt Daten, die die momentane Winkelausrichtung des Bogens 12 in Bezug auf eine gegebene Richtung anzeigen, beispielsweise in Bezug auf die zweite Richtung B;
• – erzeugt die elektronische Verarbeitungseinheit auf der Basis der Winkelausrichtungsdaten ein entsprechendes Differenzvorrückkorrektursignal, um ein unterschiedliches Vorrücken zwischen zwei in Querrichtung beabstandeten Zonen des gleichen Bogens 12 zu erzeugen und somit den Bogen um einen gewünschten Winkel in der horizontalen Ebene zu drehen;
• – sendet die elektronische Verarbeitungseinheit das Korrektursignal an mindestens einen der Motoren 77, 78, um die Rotation von mindestens einer der zwei motorgetriebenen Rollen 71, 72 zu steuern und folglich ein unterschiedliches Vorrücken zwischen den zwei in Querrichtung beabstandeten Zonen des gleichen Bogens 12 hervorzurufen und daher den Bogen um einen gewünschten Winkel zu drehen, wodurch eine Drehung des Bogens 12 in der horizontalen Ebene bewirkt wird, um die zwei Punkte an der seitlichen Kante der zwei Bezugsmarkierungen senkrecht zu der zuvor erwähnten zweiten gegebenen Richtung B, das heißt parallel zu der Klinge der zweiten Rillmaschine 60, auszurichten;
• – erfasst die elektronische Verarbeitungseinheit Vorrücksignale von dem Encoder 45, 46, um das Vorrücken des Bogens 12 in zwei in Querrichtung beabstandeten Positionen des Bogens zu erfassen; und
• – stellt die elektronische Verarbeitungseinheit aus den von den Encodern 75, 76 erzeugten Vorrücksignalen fest, dass auf dem gleichen Bogen 12 gemäß dem Korrektursignal wirksam ein unterschiedliches Vorrücken zum Bogen zwischen zwei in Querrichtung voneinander beabstandeten Zonen übertragen worden ist. 83 bezeichnet eine weitere optionale Photodetektorvorrichtung, eine Fernsehkamera oder eine Photokamera in dieser Ausführungsform. Der Photodetektor 83 kann oberhalb der Bahn angeordnet sein, gefolgt von den Bögen, um zu überprüfen, ob die Rillen 17, 18 senkrecht zueinander sind.

The rotational movements of the two motor-driven rollers 71 . 72 are controlled by an electronic processing unit (not shown) to ensure that the sheet is accurately transversely aligned and that the grooves 17 the first arrangement perpendicular to the blade 61 the second creasing machine positioned. Especially

• The electronic processing unit detects signals from the optical detection device 80 representing the positions of two laterally spaced points along a side edge 19 of the bow or two reference marks 16c . 16d on the bow 12 Show;
• The electronic processing unit processes those from the optical detection device 80 received signals and generates data showing the instantaneous angular orientation of the arc 12 with respect to a given direction, for example with respect to the second direction B;
• The electronic processing unit generates, based on the angular orientation data, a corresponding differential advance correction signal to cause differential advancement between two transversely spaced zones of the same arc 12 to generate and thus to turn the sheet by a desired angle in the horizontal plane;
• - The electronic processing unit sends the correction signal to at least one of the motors 77 . 78 to the rotation of at least one of the two motor-driven rollers 71 . 72 and hence a differential advancement between the two transversely spaced zones of the same arc 12 cause and therefore to turn the bow by a desired angle, causing a rotation of the bow 12 is effected in the horizontal plane to the two points at the lateral edge of the two fiducial marks perpendicular to the aforementioned second given direction B, that is parallel to the blade of the second creasing machine 60 to align;
• The electronic processing unit detects advancement signals from the encoder 45 . 46 to the advancement of the bow 12 to detect in two transversely spaced positions of the sheet; and
• - Represents the electronic processing unit from that of the encoders 75 . 76 produced advance signals that on the same arc 12 according to the correction signal has been effectively transferred a different advance to the arc between two transversely spaced zones. 83 denotes another optional photodetecting device, a television camera or a photo camera in this embodiment. The photodetector 83 can be located above the web, followed by the bows to check if the grooves 17 . 18 are perpendicular to each other.

The second creasing machine 60 Downstream is another sentence 26 motor driven parallel belts extending in the first direction B and extending in transversely spaced parallel planes. The set of conveyor belts 26 takes individual bows 12 on top of that by the creasing machine 60 have passed through and causes them in the second direction A to the cutting machine 90 move.

In the cutting machine 90 For example, the individual sheets may be cut and optionally given grooves along oblique or curved score lines, or in any case lines with a course that is neither perpendicular nor parallel to the first direction A, or grooves of secondary importance that are less relevant to the quality of the Affect the product.

It is understood that the grooves made along parallel lines according to this method cause a shortening of a linear type in only one direction perpendicular to the direction in which the score lines extend. Parallel score lines do not cause oblique or diagonal shortening. The linear shortening depends on various factors, including the thickness or weight of the sheet, the number of grooves or the coloration, and is known and quantifiable. Advantageously, these geometric truncation data can be taken into account as input data during the programming phase of the electronic control unit. The truncation data refers to datum points on the arc that are known to and accurately detected by the photodetectors; this makes it possible to bring the creasing lines in extremely precise and known positions. Subsequent operations performed by the cutting machine are performed using the same dots along the edges of the sheet or the same marks printed on the sheet and used to form the score lines. As a consequence, the cuts made by the cutting machine are made with absolute accuracy with respect to the creasing lines previously made on the sheet by the two creasing machines 30 and 60 were created.

The process makes it possible to quickly obtain a sheet of a different format by simply reprogramming the input data into the electronic control unit. The dead times due to changing conventional punches are eliminated.

6 illustrates another alternative embodiment of the method. On the basis of the variant in 6 be the bows 12 caused along a single direction of linear advancement from the sheet feeder 11 to the cutting machine 90 advance. In an intermediate position between the first creasing machine 30 and the second creasing machine 60 there is a turning station 85 ,

The bows 12 on which the first arrangement of grooves 17 through the first creasing machine 30 has been applied, run in direction A from the second set of motorized parallel belts 22 to a set of motorized conveyor rollers 86 which run transversely to the advancing direction A.

A rotation element 87 that on rollers 86 is applied in a lateral position with respect to a middle advance line, engages the upper surface 15 every bow that passes over the rollers 86 runs and causes it to rotate 90 ° in a horizontal plane (arrow C). A straight Longitudinal edge (not shown) may be along one side of the turning station 86 be created. The rotary element 87 For example, it may have a pin (for example made of rubber or other material with a high coefficient of friction), each against an eccentric or lateral point on the sheet 12 that on the rollers 86 advances, becomes wedged and releases after the arc has been rotated. As an alternative, the rotary member may comprise a pivot clamp (not shown) that supports the arch 12 turns 90 ° in the horizontal plane.

From the turning station 85 get individual bows 12 to a set of motorized parallel bands 25 which extend in the advancing direction A. As in the case of 1 and 2 described, cause the bands 25 that the bows towards the second creasing machine 60 advancing a second array of straight parallel score lines 18 on each sheet applies, perpendicular to the score lines 17 the first, previously from the first creamer 30 extend generated arrangement. Subsequently, the single sheets of the cutting machine 90 fed in the same way as in the embodiment in 1 and 2 ,

In contrast to the embodiments shown here, the blades of the creasing machines 31 . 61 be short with respect to the sheets when it is desired to produce part grooves.

With reference to the 7 and 8th For example, one embodiment of this invention contemplates the use of a single creasing machine that provides the first array of creasing lines 17 and then the second arrangement of score lines 18 perpendicular to the lines 17 the first arrangement generated. In a similar manner as for the embodiments in FIGS 1 to 2 described, becomes a preprinted sheet 12 ( 7 ) advanced along a predetermined path and through the creasing machine 30 guided, which successively a first arrangement of straight grooves 17 generated on the bow. The bows 12 which have received the first arrangement of creasing lines, become the sheet feeding device again 11 fed, which is rotated by 90 ° ( 8th ). The sheets are then again passed through the creasing machine, forming a second array of creasing lines 18 perpendicular to the first creasing lines 17 receive. In this way, a grid of score lines is obtained in two perpendicular directions on each sheet. Again, in this embodiment, the score lines are transmitted at predetermined intervals with respect to reference points located on the sheet (for example, reference points along their edges or reference marks printed on a surface of the sheets). The reference points are by optical devices 50 recorded with appropriate alignment devices 40 Similar to those mentioned with reference to the 1 to 2 described are operatively linked. The sheets with the grid of vertical creasing lines then become the cutting machine 90 supplied in a similar manner, as in the embodiments in the 1 and 2 the case is.

With reference to 9 to 11 These represent a further embodiment of this invention in which the advancement of the individual sheets without the in the 1 to 8th detected encoders with wheels is detected. According to the variant in 9 to 11 the advancement of the sheets is detected by one or more optical detectors which detect the passage of pairs of notches or fiducials printed on the sheet near or in the positions where it is intended that the grooves are to be formed.

A plurality of fiducials are printed in transversely spaced positions with respect to the direction of advancement and are aligned parallel to the straight score lines that it wishes to form. A pair of transversely spaced optical detectors are the photocells in the illustrated embodiment 51 . 52 the or each creasing machine 30 mounted upstream (and 60 if a second creasing machine is provided). The two optical detectors detect the passage of the two fiducial marks forming part of the same pair of transversely aligned fiducial marks and send two corresponding signals indicative of the instantaneous longitudinal position or advancement of the two fiducial marks to the processing unit. Thus, if an oblique misalignment of the two fiducial marks is detected, the processing unit controls the rotational speed of one of the electric motors to cancel the misalignment and cause the transverse sheet to advance through the creasing machine with the notch pairs parallel to the blade of the creasing machine.

With reference to 12 and 13 Yet another embodiment of this method includes the use of a single creasing machine 30 one that is both the first episode of crease lines 17 and then the second episode of score lines 18 perpendicular to the lines 17 the first arrangement transmits. In a similar manner as for the embodiment of 7 and 8th described, becomes a preprinted sheet 12 ( 12 ) advanced along a predetermined path and passes through the creasing machine 30 giving the bow a first series of straight creasing lines 17 transfers.

Then the movement of the transport system is reversed ( 12 , Arrow D), and the bow, which is the first arrangement of creasing lines 17 has received first, the creasing machine again 30 recorded upstream, then it is rotated in the horizontal plane by 90 ° ( 13 , Arrow E) and then it is again passed through the creasing machine, creating a second series of creasing lines 18 perpendicular to the first creasing lines 17 receives. In this way, a grid of score lines is obtained in two perpendicular directions on each sheet. Also in this embodiment, the score lines are transmitted at predetermined intervals with respect to the reference points disposed on the sheet as for the other embodiments described above.

The rotation of the sheets in the horizontal plane can preferably be performed by the two motorized rollers 41 . 42 be set in motion in two opposite directions of rotation. In the reversal phase ( 12 ) can the bow 12 be moved backwards until the optical reader 51 and 52 detect the passage of the new leading edge of the sheet.

The fiducial marks may be located at the edges of the sheet to subsequently pass through the cutting machine 90 to be removed, which cuts off the edges.

In all possible embodiments of the method, the fiducial marks or fiducials may be printed on one or both of the opposite sides of the sheets, for example on the top surface and / or the bottom surface. Consequently, the optical detection of the reference numerals can be made from the side having the bow marks, namely from above and / or from below.

As an alternative to two transversely spaced photocells or optical detectors, the optical detection device may comprise a single television camera or a photocamera capable of reading the positions of both fiducial marks forming part of the same pair of transversely spaced fiducial marks.

The programming of the processing unit is simplified by placing the fiducials at or near the locations intended for scoring. In order to know the position of the score lines with certainty, no correction factors have to be taken into account in order to evaluate the shortening of the signature as a result of the generated score lines. In fact, a minimum or zero distance between the fiducials and the crease lines eliminates uncertainty about the actual position of such lines.

Various aspects and embodiments of methods for processing sheet materials have been described. It is intended that each embodiment should be capable of being combined with any other embodiment. The invention is not limited to the embodiments, but may be varied within the scope defined by the appended claims.

Claims (15)

A method of processing sheet materials, comprising the steps of: - causing a preprinted sheet ( 12 ) advances along a predetermined path in a first horizontal advancing direction (A); Optically detecting the positions of at least one pair of first reference points ( 16a . 16b ) on said sheet, said two first reference points of a same pair being transversely spaced apart in a direction substantially perpendicular to said first advancing direction (A); Based on the optically detected positions of the first pair of reference points, obliquely aligning the arc in a horizontal plane with respect to the first advancing direction (A); Causing the slanting sheet to advance in the first advancing direction and sequentially forming a first array of straight and parallel score lines (FIG. 17 ), which are spaced in the first advancing direction (A), wherein the creasing lines ( 17 ) have an orientation and distances with respect to the at least one pair of first reference points; Optically detecting the positions of at least a second pair of second reference points ( 16c . 16d ) on the sheet, wherein the two second reference points of a second pair of dots are spaced in a direction perpendicular to the direction in which the two first reference points of the at least one first pair of reference points are spaced from each other; Based on the optically detected positions of the second pair of reference points, obliquely aligning the arc ( 12 ) in a horizontal plane with respect to a second advancing direction (B), - whereby the transversely oriented sheet in the second advancing direction (B) is advanced and a second arrangement of straight and parallel score lines is formed (18), wherein the lines of the second arrangement of Creasing lines - have an orientation that points to the second pair of second reference points of the arc ( 16c . 16d ) and extends perpendicular to the first array of score lines, with respect to the two second reference points (FIG. 16c . 16d ) are spaced apart from each other, and - define, along with the lines of the first array of score lines, a pattern of vertical score lines; and - feeding the sheet to a processing machine ( 90 ) to the bow using at least two of the first ( 16a . 16b ) or second ( 16c . 16d ) To cut reference points as a reference. The method of claim 1, wherein: the first (A) and second (B) advancing directions are successive advancing directions, forming an angle between them, and together define a substantially L-shaped path for the sheets; the first arrangement of score lines ( 17 ) by a first creasing machine ( 30 ) is formed; the second arrangement of score lines ( 18 ) by a second creasing machine ( 60 ) is produced; deflect the sheets obliquely from the first (A) to the second advancing direction (B) in a deflection station, which is the first creasing machine ( 30 ) and the second creasing machine ( 60 ) is arranged upstream. The method of claim 2, wherein the sheets deflect substantially from the first (A) to the second (B) advancing direction without being rotated in a horizontal plane. Method according to claim 2 or 3, in which the sheets are pressed against a side stop ( 23 ), which extends in the second advancing direction (B). Method according to one of claims 1 to 4, wherein the first (A) and the second (B) advancing direction form an angle of about 90 °. The method of claim 1, wherein the first (A) and second (B) advancing directions are consecutive and substantially aligned advancing directions which together define a substantially straight path for the sheets; the first arrangement of score lines ( 17 ) by a first creasing machine ( 30 ) is formed; the second arrangement of score lines ( 18 ) by a second creasing machine ( 60 ) is formed; and where the bows ( 12 ) in a horizontal plane through 90 ° in one between the first creasing machine ( 30 ) and the second creasing machine ( 60 ) arranged intermediate rotary station ( 85 ) to be turned around. The method of claim 1, wherein the first (A) and second (B) advancing directions coincide and define a single advancing direction; the first and the second arrangement of score lines ( 17 . 18 ) by the same single creasing machine ( 30 ) be generated; the first arrangement of score lines ( 17 ) is formed by the sheet is advanced a first time in the single advancing direction and the sheet for the first time by the creasing machine ( 30 ), the arc having a certain angular orientation with respect to the single advancing direction; the second arrangement of score lines ( 18 ) is formed by advancing the sheet a second time in the single advancing direction and causing the sheet to be fed a second time through the same creasing machine ( 30 ), wherein the sheet has an angular orientation which is rotated by 90 ° with respect to the angular orientation angle taken from the same sheet when it first passes through the creasing machine. The method of claim 1, wherein the first (A) and second (B) advancing directions coincide and define a single advancing direction; the first and the second arrangement of score lines ( 17 . 18 ) by the same single creasing machine ( 30 ) be generated; the first arrangement of score lines ( 17 ) is formed by the sheet is advanced a first time in the single advancing direction and the sheet for the first time by the creasing machine ( 30 ), the arc having a certain angular orientation with respect to the single advancing direction; the second arrangement of score lines ( 18 ) is formed by first causing the sheet to move backward in an opposite direction with respect to the single advancing direction, to return the sheet to the single-seed (FIG. 30 ), then turning the sheet through 90 ° in a horizontal plane and then causing the sheet to be fed a second time through the same creasing machine ( 30 ), wherein the sheet has an angular orientation which is rotated by 90 ° with respect to the angular orientation angle taken from the same sheet when passing through the single grooving machine for the first time (FIG. 30 ) running. Method according to one of claims 2 to 8, wherein the first ( 30 ) and / or the second ( 60 ) Creasing machine comprise either creasing machines or folding machines that are configured to just transmit creasing lines. Method according to one of the preceding claims, wherein the steps of optically detecting the positions of the pairs of reference points ( 16a . 16b ; 16c . 16d either by detecting the positions of two respective transversely spaced points on an edge (FIG. 14 . 19 ) of the bow ( 12 ) be performed; Or by detecting the positions of at least one pair of fiducials ( 16a . 16b ; 16c . 16d ) which are spaced transversely and on the arch ( 12 ) are printed. Method according to one of the preceding claims, wherein the steps of obliquely aligning the sheet with respect to the first (A) or the second (B) advancing direction are performed by controlling at least two electric motors on the basis of optically detected position data of the pairs of points which are driven independently of each other and drives two respective rollers, which at the same time on the same sheet ( 12 ), wherein the two rollers are spaced from each other in a transverse direction with respect to the first or second advancing direction, so as to provide differential advancement between two laterally spaced apart portions of a same arc ( 12 ) and, as a result, cause the arc to rotate through a desired angle in a horizontal plane. The method of claim 11, wherein the electric motors of the rollers are controlled based on at least two advancement signals related to transversely spaced zones of a sheet, the signals of advancing at least two encoders ( 49 . 59 ), each one rolling element ( 45 . 46 ), wherein the two rolling elements are configured to unroll on the sheet in two respective zones spaced transversely to the sheet. Method according to claim 12, wherein the two rolling elements ( 45 . 46 ) are respectively disposed adjacent to the respective motor-driven roller, preferably downstream thereof with respect to the direction of forward movement of the sheet. A method according to any one of claims 1 to 10, comprising optically detecting positions of a plurality of pairs of fiducial marks on one and the same sheet ( 12 ), wherein two fiducial marks of a same pair are disposed at positions transversely spaced with respect to the advancing direction, and wherein the pairs of fiducial marks are spaced from each other in an advancing direction perpendicular to the direction along which the fiducial marks follow each other Pair are spaced apart. The method of claim 11, wherein at least some of the pairs of fiducials adjacent the opposite edges of a same arc ( 12 ) to be printed.

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