EP1531045A1 - Process for positioning and transferring at least two different patterns from a transfer foil - Google Patents

Abstract

The method involves moving a conveyor belt at a constant speed equal to that of a substrate (c) during transfer of patterns. Moving time of the belt is subtracted from a time between passages of two similar marks of zones in the belt. The value of displacement of adjacent patterns between respective locations is compared with a length calculated between the adjacent patterns, to coincide the transfer of the patterns with respective locations on the substrate.

Description

The present invention relates to a method for position and transfer at least two different patterns cut from a feed belt with a succession of at least two specific zones, one for each of said patterns, on a strip substrate driven to constant speed, according to which said band is driven feeding at a constant speed equal to that of said web substrate during the transfer of each of said patterns and according to a determined velocity profile between two transfers of said motifs.

In the presses used to transfer patterns on a strip substrate, especially a metallized strip, each band can only transfer one pattern. Given the impossibility of having several bands on the same trajectory, it is therefore possible to file only one ground on this trajectory.

It has already been proposed in EP 441 596 a device to transfer, from a support strip of a material deposited images of this material into determined locations of a strip substrate, driven to constant speed. In such a device, it is obvious the length of the deposited material consumed does not constitute than a fraction of that of the web substrate. Now, the band support of the material to be deposited is formed of a laminate of which The price is high. That's why we proposed in the aforementioned document means of movement having means for reversing longitudinal displacement of the support band of the material to be deposited, these means in the opposite direction being respectively arranged upstream and downstream means for the transfer of the image of the support strip to the strip substrate, so to reduce on the support band, the space separating two images in order to save as much as possible of this support band.

This device saves the power strip, but the tape management process does not allow to position and transfer groups of different patterns from the same feed band, especially groups of patterns comprising at least one hologram per group.

The object of the present invention is to provide a solution to this problem.

For this purpose, this invention relates to a process according to claim 1.

Thanks to this process, it becomes possible to deposit different patterns that lie on the substrate on the trajectory of the same feed band, which would have required so far several bands on the same trajectory and was therefore obviously impossible to achieve. He becomes especially possible to transfer, with all the precision required, holograms, since this process does not allow plus only precise positioning of the transfer tool compared to the printing of the substrate but also a precise positioning of the hologram compared to the shot transferring this hologram onto the substrate.

Consequently, the method according to the invention offers possibilities still unknown so far in the field of pattern transfer on a strip substrate. This is how that can be transferred, with all the necessary precision, at least one hologram on a group comprising at least two different successive motifs transferred. We can transfer, for example, using the same band, besides one or several holograms, one or more metallized patterns standards of different colors, or pattern producing the diffraction of light. Just have a band with as many specific areas successive that there are reasons in a group of patterns, successive groups each presenting the same succession specific areas. The lengths of these areas, other than the one (s) of the hologram can be chosen to cover a certain range of pattern lengths, so that a same power strip can be used to perform the transfer of different patterns.

As a result, the user will have essentially to choose the hybrid power strip depending on the number of reasons to be transferred using this band. We will have essentially bands with 2, 3, 4 specific areas, even more. If a hologram is to be transferred, it will be formed before the transfer to one of the zones specific. The method according to the invention makes it possible to have a precise positioning of this hologram as well vis-à-vis the transfer tool that vis-à-vis the location of the substrate on which it is to be deposited. It's in effect in the case of the transfer of a hologram that the process according to the invention is of the greatest interest. The transfer of other patterns does not require positioning precise than the transfer tool with respect to the substrate, as long as this reason has to be positioned relative to to a prior impression. Compared to the feeding belt, it is only necessary that the tool comes to cut the reason to transfer to the specific area, but as this area is usually longer than the pattern, the accuracy with respect to this area does not have the same importance only for the hologram.

The attached drawing illustrates, schematically and by way of example, an embodiment of the mode of implementation of the process object of the present invention.

FIG. 1 is an explanatory diagram of this mode of setting implemented;

FIG. 2 is a diagram of the respective displacements of the web substrate and the web of function of time;

We will refer essentially to the diagram of Figure 1 for the explanation of the process according to the present invention. It shows a rotary press comprising a cylinder cylinder 1 carrier, in this example, of three groups of three pictures each h1, f1, g1; h2, f2, g2; h3, f3, g3. The clichés h1, h2, h3 are identical, so are the snapshots f1, f2, f3 and snapshots g1, g2, g3. So all groups of three snapshots are formed of identical snapshots and spacing between successive snapshots are also identical from one group to the next, so that it is peer groups.

A support cylinder or counter-cylinder 2 is located vis-à-vis the cylinder 1 and two bands bm and c pass between the cylinders 1 and 2. The band c constitutes the substrate on which are transferred patterns cut by the pictures h _i , f _i , g _i on the feed belt bm, generally constituted by a metallized strip. The band c constituting the substrate may be a strip of cardboard, especially cardboard for forming box poses, after cutting the strip c into separate sheets or sheets. When used in the process according to the present invention, this cardboard strip has already undergone various operations, the main one being printing.

The patterns transferred on this substrate must therefore be precisely positioned relative to the impression made beforehand on this substrate. Position adjustment clichés on the substrate is obtained by adjusting the position angle of a snapshot on the cylinder 1, compared to the impression carried by the substrate c. This operation is conventional and is not part of the process according to this invention, but constitutes a preliminary adjustment operation any transfer of patterns on a substrate carrying a impression.

In the diagram of Figure 1, there is shown four groups of three specific areas each corresponding to one of the reasons to transfer. Zones H1, F1, G1; H2, F2, G2; H3, F3, G3; H4, F4, G4 are represented with shapes different, the peer areas of each group having the same forms. This is done to facilitate the explanation, in In reality, these areas will consist of rectangles more or less long, of the same width as the feeding belt.

In the example described, it is assumed that the zones H _i correspond to a hologram. Each hologram of the zones H _i is associated with a marker m1, m2, m3, m4 formed with the hologram and whose position is characteristic of that of the hologram. For reasons of manufacture of the metal strip bm, the positioning of the holograms can not be guaranteed with sufficient precision, so that the spacings L _i between the adjacent marks m _i , the positions of which are strictly characteristic of the position of the holograms , may vary slightly.

It exists on the rotary presses to report patterns on a strip substrate, such as that used for the implementation of the method according to the present invention, a zone zi not accessible to perform a position measurement on the feed strip bm . As a result, it is not possible to place a marker detector m _i in the immediate vicinity of the forme cylinder 1, which would obviously be desirable. This is why a detector T1 is disposed upstream of the cylinders 1, 2.

Since it is preferable to read the marks m _i when the supply band is moving at a constant speed, it is therefore preferable to have the detector t 1 at a distance from a reference plane passing through the two axes of rotation of the two cylinders 1, 2. It is on this reference plane that the transfer of the patterns by the pictures h _i , f _i , g _i , the feed band bm to the substrate strip vs. The distance between this reference plane containing the axes of the cylinders 1, 2 and the detector t1 corresponds to n times L, L corresponding to an average of the variable L _i , so that the reading corresponds to a period during which the band of supply moves at a constant speed, since it must accompany the platen cylinder 1 during the pattern transfer operation to the c-band substrate, the cylinder 1 rotating at a constant speed. In the formula nx L of the illustrated example giving the distance separating the reference plane of the detector tl, n is equal to 3.

To save the material of the feed band bm, the distance separating the specific specific areas H _i , F _i , G _i on this supply band bm is obviously reduced and does not correspond to that which will separate the patterns cut in these respective specific areas and deposited on the substrate c. The difference between the distance between two adjacent patterns on the feed band bm and the distance between these two same patterns on the c-band substrate constitutes a constant basic parameter, integrated in the control processor to develop the speed profile of the feeding belt bm.

Once done the angular positioning of the cylinder slide carriers 1 with respect to printing marks (not shown) carried by the c-band substrate, the positioning method according to the present invention is implemented as follows:

The reading by the detector tl of the mark m1 on the strip bm power supply is triggered in angular positions determined from the cylinder, which correspond to the alignment clichés h1, h2, h3 with the plane joining the axes of the two cylinders 1, 2 and which corresponds to the position of transfer of the holograms of the zones H1, H2, H3 of the band supply bm to the c-band substrate, during which time the feed band bm moves at a constant speed.

The detector T1 measures the existing gap e1 at this instant precise, between a reference position in which should be the m1 mark and its actual position. Let that this gap e1 = -0.2 mm. The correction k1 to perform is therefore k1 = -e1, so k1 = +0.2 mm.

The calculated position of the next snapshot h2 by the plane joining the two axes of the cylinders 1, 2, triggers the reading by the detector tl of the m2 mark characteristic of the position of the H2 hologram. If the measured difference is example e2 = +0.1 mm, we memorize the new correction modified for the position of the hologram H1 is k11 = -e1-e2, therefore k11 = +0.1 mm.

We also memorize a first correction for the position the hologram H2 is k2 = -e2, so k2 = -0.1 mm.

The calculated position of the snapshot h3 by the plane joining the two axes of the cylinders 1, 2, triggers the reading of the m3 mark characteristic of the position of the H3 hologram. If, for example, a gap e3 = -0.4 mm is observed, a new correction modified for the position of H1, let k111 = -e1-e2-e3, here k111 = +0.5 mm. We memorize a modified correction for H2 position is k22 = -e2-e3, here k22 = +0.3 mm and we still memorize a first correction for the position of the hologram H3 is k3 = -e3, here k3 = +0.4 mm.

Correction k111 is used to determine the speed profile of the feed band bm so that H1 coincides exactly with the angular position of the cliché h1 on the cylinder 1.

At the precise moment when the calculation determines that the plate is aligned on the plane connecting the two respective axes of the cylinders 1, 2, the reading of the m4 mark characteristic of the position of the hologram H4 is triggered. A gap e4 is measured, for example e4 = -0.3 mm. The correction k1 is then erased from the memory which keeps only the data relative to the marks m _i located between the detector tl and the plane containing the axes of the two cylinders 1, 2.

The diagram in Figure 2 illustrates the respective profiles displacements (mm) of the substrate strip c and the metallized supply belt bm as a function of time (S). In parallel with the abscissa, the substrate strip c with the deposited patterns and parallel to the ordinate, the bm feed band with its specific areas for the deposit of the different reasons.

It can be observed that the respective speeds of the bands V (c) and V (bm) are the same when filing the patterns of the feed band bm on the substrate strip c, the profiles of respective displacements of these bands c and bm being parallel. The substrate strip c moves at a constant speed, so that his speed profile is a straight line. When the two bands c, bm move at the same speed, their profiles are parallel. Between the deposits of two successive patterns, the speed profile of the feed belt bm is adapted according to the displacement that the substrate in band c must travel at a constant speed, to the location on which the next pattern and moving a lot shorter than must go through the bm power strip to go from one specific area to the next.

As already mentioned, the precision required for the positioning of these different zones is not very great. It is against it for the positioning of holograms H _i . In this case, the velocity profile is determined using the correction mode previously described between the detector t1 and the transfer of the hologram. Note that the number n of lines of the memory can vary according to the work and the number of patterns of each group of patterns.

The processor used to carry out the control of the speed profile of the drive device of the feed band bm is programmed according to the average parameters relating to the lengths L _i between the successive groups of specific zones H _i , F _i , G _i , the constant speed of the c-band substrate and differences in lengths between the distances separating the successive patterns on the feed band bm and those which separate these same successive patterns on the c-band substrate. To these parameters are added, to each measure of difference between the position of a mark m _i measured in the calculated passage of the pictures h _i on the plane joining the axes of the cylinders 1, 2 and a reference position for this same mark, the correction to be made to take account of this difference and which corresponds to the inverse of this difference. All the deviations of the markings situated between the detection position and the transfer position of the holograms H _i on the substrate are added so that the correction performed on the hologram H _i arriving in the transfer position occupies a position corresponding exactly with the cliché. h _i cylinder 1 of the rotary press when it coincides with the precise location of the impression carried by the substrate c.

In this way, at each hologram transfer H _i on the c-band substrate, a correction of the position of the band b m is superimposed on the standard speed profile of the control processor of the training device, so that the hologram H _i carried by the feeding belt bm coincides exactly with the picture h _i cylinder 1.

Claims (6)

Method for positioning and transferring at least two different series of patterns (H _i , F _i , G _i ) cut from a feed band (bm) on which a succession of groups formed of at least two zones is arranged specific, one for each of said patterns, on a substrate (c) in a band driven at a constant speed, wherein said feed strip (bm) is driven at a constant speed equal to that of said substrate strip (c) during the transfer of each of said patterns and according to a determined velocity profile between two transfers of said patterns, said velocity profile is determined by measuring the time elapsing between the passes of two homologous marks (m _i ) of two successive groups of said two specific zones, from this time, the travel times of said supply band (bm) are deduced during the transfers of said two patterns, the length is calculated between said respective adjacent patterns (H _i , F _i , G _i ) su r said feed band (bm) and is compared to the length of the displacement between the respective locations of the same two successive patterns on said substrate (c), to match the transfer of said patterns with their respective locations on said substrate (c) ). The method of claim 1, wherein said successive patterns (H _i , F _i , G _i ) are positioned relative to a prior printing of said substrate (c). Method according to one of the preceding claims, wherein a hologram (H _i ) is formed on at least one of said specific areas of each of said groups. Method according to Claim 3, in which, at given times and at a given distance from a reference point, the difference between the position of each of the successive markers (m _i ) characteristic of the position of each hologram is detected ( H _i ) and said given distance, a specific velocity profile is determined for moving each hologram (H _i ) over said given distance, by measuring the deviation of each of said respective marks (m _i ), generating a correction of said deviation and by summing said corrections of all the markers (m _i ) located between said detection point and said reference point. The method of claim 4, wherein said given distance is n times the length of a group specific areas upstream of said reference point. Method according to one of the preceding claims, according to which the length of each of said areas according to that of the longest desired pattern.

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