WO2009087440A2

WO2009087440A2 - Floor covering, formed from floor panels and method for manufacturing such floor panels

Info

Publication number: WO2009087440A2
Application number: PCT/IB2008/003498
Authority: WO
Inventors: Oke Nollet; Benny Schacht; Peter Provoost; Lode De Boe
Original assignee: Flooring Industries Limited, Sarl
Priority date: 2008-01-09
Filing date: 2008-12-16
Publication date: 2009-07-16
Also published as: EP2250033A2; WO2009087440A3; US20100285289A1; WO2009087440A9

Abstract

Method for manufacturing covered panels, wherein these covered panels (19) comprise at least a basic panel (28) and a top layer (29) with a printed motif (32), wherein the method comprises at least the step of forming a decorative print (2) on a substrate (3) by means of at least two printing cylinders (1A-1 B), characterized in that said decorative print (2) is composed at least of a first print pattern (4) and a second print pattern (5) at least provided by means of a first (1A) and a second (1 B) of said two printing cylinders (1), respectively, and that the decorative print (2) is formed such that it comprises at least a zone (11) in which said first print pattern (4) is absent.

Description

Method for manufacturing covered panels and covered panel obtained thereby.

This invention relates to a method for manufacturing covered panels, as well as to a covered panel that can be obtained thereby.

More particularly, the invention relates to a method for manufacturing covered panels comprising at least a basic panel and a top layer with a printed motif provided on this basic panel. Herein, this may relate, for example, to furniture panels, ceiling panels, floor panels or the like, which substantially consist of a MDF or HDF (Medium or High Density Fiberboard) basic panel and a top layer provided thereon, such as a laminate top layer.

Covered panels or floor panels of the above-mentioned type are known as such. Herein, the printed motif, whether or not by the intermediary of primer layers, can be printed directly on the basic panel or on a basic board comprising this basic panel. However, initially the print may also be provided on a flexible material sheet, such as a paper sheet, wherein this printed material sheet then as such, as a so- called decor layer, is taken up into said top layer of the covered panel or floor panel. Further, it is known that such panels can be provided with a transparent or translucent synthetic material layer, which forms a protective layer above the printed motif and may comprise, for example, wear-resistant particles, such as aluminum oxide. It is not excluded that this protective layer also comprises a material sheet, such as a paper sheet.

In the case of a laminate floor panel, manufacture may be performed, for example, according to a DPL (Direct Pressure Laminate) or HPL (High Pressure Laminate) technique. In the case of a DPL technique, one or more material sheets provided with resin, amongst which a printed material sheet forming a decor layer, are brought together with the basic panel or with a larger basic board into a press device, where, by means of a press element and under the influence of increased pressure and temperature, they are connected to each other as well as to the basic board. In the case of a HPL technique, the top layer is formed separately on the basis of two or more material sheets provided with resin, amongst which a printed material sheet forming a decor layer, before the thus obtained top layer is provided on the basic board, for example, by gluing it onto the basic board. It is known that the printed motifs of such covered panels can be obtained by means of a method which comprises at least the steps of forming, by means of printing cylinders on a substrate, either on a flexible material sheet, or directly on a board-shaped substrate, a larger decorative print and of forming said covered panels by means of at least a portion of this substrate and the decorative print provided thereon. Herein, for the step of forming the decorative print, this relates in particular to the technique of rotary offset printing, which, for printing on board- shaped substrates, is known, for example, from US 3,173,804 and EP 1 862 304, and for printing on flexible material sheets is known, for example, from EP 1 541 373. In these known techniques, the length of a print pattern obtained by means of printing cylinders is limited by the circumference of the printing cylinder. This means that, when one wants to realize covered panels with a printed motif that is longer than the circumference of such printing cylinder, this printed motif will show a repetition of at least a portion of the respective print pattern. It is noted that the length of such print pattern usually is smaller than 1.4 meters. For the step of forming the covered panels, a variety of techniques can be applied, such as, for example, a DPL technique, wherein the decorative print printed on a flexible substrate is used as a decor layer and is pressed on a larger basic board. The obtained pressed whole then is divided into smaller panels having approximately the dimensions of the final covered panels, such as floor panels.

In order to remedy the disadvantages of the offset printing technique, it is suggested, amongst others, in WO 2007/076853, to print transversely. This means that the printed motifs of the covered panels are obtained from a larger print in which these printed motifs extend transversely instead of parallel to the printing direction. In this manner, printed motifs can be realized with a length approximately corresponding to the width of the printing cylinders, without repetitions occurring in this printed motif. The width of the printing cylinders usually is larger than their circumference and may be, for example, approximately 2 meters. By this method, it is impossible to obtain printed motifs which are longer than the length of the printing cylinders, and this independently of the fact whether one wants to accept repetitions of the printed pattern or not. Moreover, due to this circumference-width- ratio of the printing cylinders in transverse printing, the number of possibly obtainable covered panels with different motif is smaller than with the usual longitudinal printing, wherein the printed motifs extend in the larger print parallel to the printing direction.

It is noted that a possible utilization of printing cylinders with a larger diameter and circumference for realizing longer print patterns of course is limited by the construction of the printing device concerned.

According to the state of the art, it is indeed possible to form larger printed motifs without repetitions by means of digital printing techniques, such as inkjet printing. However, these techniques are less fast and thus less economic than a technique in which printing cylinders are applied, such as it is the case with the technique of rotary offset printing, performed on a flexible material sheet or directly on a board- shaped substrate, whether or not with the utilization of intermediate layers previously provided on this board-shaped substrate.

The present invention aims at an alternative method for manufacturing covered panels, which method, according to preferred embodiments thereof, offers advantages in respect to the printing techniques known from the state of the art. So, for example, it aims at a method which allows realizing in a smooth manner printed motifs in longitudinal printing which are longer than the cylinder circumference and still do not show any repetitions in the print pattern, and allows, in longitudinal printing as well as in transverse printing, increasing the number of possibly obtainable covered panels with a different printed motif. To this aim, the invention relates to a method for manufacturing covered panels, wherein these covered panels comprise at least a basic panel and a top layer provided on this basic panel having a printed motif, wherein the method comprises at least the steps of forming a decorative print on a substrate by means of at least two printing cylinders and forming said covered panel by means of at least a portion of this substrate, with the characteristic that said decorative print is composed at least of a first print pattern and a second print pattern provided at least by means of a first and a second of said two printing cylinders, respectively, and that the decorative print is formed such that it has at least a zone in which said first print pattern is absent, whereas said second print pattern in its turn is present in the zone concerned. It is clear that the printed motif of at least one of said covered panels is formed by means of at least a portion of the zone concerned. By realizing zones in which one of the print patterns remains absent, a larger variety in the larger print is obtained, which then also results in a larger variety of covered panels with printed motifs.

It is clear that according to the invention, this preferably relates to first, second and/or further print patterns showing different motifs.

It is also clear that, the more printing cylinders and print patterns according to the invention are applied, the larger said variety can be. However, a considerable improvement is already achieved with two print patterns. Of course, it is preferred that the print patterns concerned are performed in color and that to this aim, these print patterns as such in each case preferably are realized with at least three printing cylinders, respectively, wherein each printing cylinder is responsible for a color present in the print pattern. According to a particular embodiment thereof, the step of printing may be performed by means of a printing device with six printing cylinders or more.

The above-mentioned larger variety of covered panels may manifest itself, for example, in that the technique of the invention allows forming more covered panels with a different printed motif from the same larger print, and/or in that this technique allows forming longer covered panels without any repetition of a portion of the print pattern occurring in the decor of these covered panels.

Preferably, the decorative print is formed such that it comprises at least a zone in which said second print pattern is absent, whereas said first print pattern in its turn is present in the zone concerned. It is clear that in this case the printed motif of at least one of said covered panels is formed by means of at least a portion of the zone concerned. It is clear that by means of this embodiment, a still larger variety is obtained. According to a preferred embodiment thereof, the zone in which the first print pattern is absent connects, whether or not by means of a transition portion, to a zone in which the second print pattern is absent. By omitting a second print pattern to the advantage of a first print pattern and vice versa, any repetition of the print pattern can be avoided in a smooth manner.

The above-mentioned transition portion may relate, for example, to a zone in which the print patterns concerned are made overlapping or complementary. By "complementary", it is meant that they both determine the final appearance of the larger decorative print in this transition portion, without necessarily being provided one above the other.

According to a first important preferred embodiment, the zone in which the first print pattern is absent is made seamless in respect to an adjacent zone of the decorative print in which this first print pattern in its turn then is present. The seamless transition between the zones concerned leads to an invisible or at least hardly visible transition among both print patterns, such that printed motifs for covered panels can be obtained from the decorative print, which motifs comprise portions of both print patterns without rendering the transition concerned too obvious. Herein, preferably at least the pattern of said larger print is made uninterruptedly at least at the height of the transition. Herein, this may relate, for example, to a pattern of wood nerves and/or wood pores extending uninterruptedly over said transition.

According to a second important preferred embodiment, the step of forming the covered panels comprises at least a partial step in which the larger print is divided by means of cutting lines, and during the preceding step of forming the larger print, the transition between the first and the second print pattern is provided there, where such cutting line is to be provided. Such transition needs not necessarily be invisible, and in this transition, the pattern of the larger print does not necessarily have to be uninterrupted, as according to this preferred embodiment the transition concerned does not form part of a printed motif of a covered panel. According to this embodiment, it is possible to obtain covered panels or floor panels with usual dimensions, namely with a length approximately corresponding to the circumference of the applied printing cylinder, which nevertheless have a larger variety, as the second print pattern may comprise other printed motifs than the first print pattern.

Preferably, said two printing cylinders are rolled off in printing direction at least over a portion of their mantle surface, whether or not directly, over the substrate, wherein the length of the print patterns concerned extends in printing direction.

Herein, this may relate to so-called transverse printing as well as to so-called longitudinal printing. In case of an indirect print, the print image of the printing cylinders concerned, for example, first may be transferred to a transfer element, preferably a transfer element with the shape of a roller or a cylinder, such as a rubber blanket cylinder, wherein this transfer element, whether or- not by means of further transfer elements, forms the final respective portion of the print on the substrate. The use of somewhat compressible transfer elements, such as one or more rubber blanket cylinders, which form the final respective portion of the print on the substrate, has the advantage that the risk that with a certain degree of unevenness in the substrate an interruption in the print will occur is minimized.

Preferably, for forming said zone in which the first print pattern is absent, the printing cylinder concerned is moved away from the substrate, or vice versa. It is also possible, whether or not in combination with the above, to provide the printing cylinder concerned with an active printing surface which is smaller than its mantle surface. Such printing cylinders can be moved away from the substrate in a smooth manner. The fact that they do not or hardly print over a certain rotation angle, gives the device intended for this purpose the time to move this cylinder away from the substrate or vice versa, without having to slow it down completely. Preferably, the active printing surface is at least one half of the mantle surface, and still better at least 75% thereof. For moving away the substrate, devices intended for this purpose may be provided in the printing device. For example, one may work, certainly in case of a flexible substrate, with asymmetric impression cylinders, which reduce the pressure when the non-active printing surface of the printing cylinder concerned is being directed towards the substrate. Such asymmetric impression cylinders are known as such for other printing applications, for example, from EP 1 935 642.

It is clear that according to the invention preferably the technique of the so-called rotary offset printing is applied for printing on the substrate. Other techniques, such as intaglio printing by means of cylinders, are not excluded.

It is noted that for the printing cylinders, cylinders can be applied wherein a printing plate is provided on the circumference of these cylinders, wherein this printing plate then shows a print image. Such printing cylinders are also called plate cylinders. Another possibility is providing the mantle surface of the cylinder itself with a print image. For an example of print images provided on the mantle surface of cylinders, reference is made to US 6,565,761 and US 3,759,800, wherein from this latter document it is also known as such to perform such print images in a seamless manner, which means that the mantle surface of such cylinders does not show seams in the print image. Further, it is noted that, as aforementioned, such printing cylinders possibly first can form an image on a transfer element, for example, on a rubber blanket cylinder, which then, whether or not by means of further transfers, provides the image on the substrate concerned. In such case, it is of course at least the last transfer element, such as the rubber blanket cylinder, which is moved away from the substrate in order to interrupt the print concerned, or which is rolled on this substrate for forming the print pattern concerned.

Preferably, for printing the substrate a printing device is applied comprising at least four printing cylinders, wherein, as aforementioned, at least one of these four printing cylinders realizes a discontinuous print pattern on the substrate. According to a particular embodiment, as aforementioned, a printing device is used which comprises at least 6 printing cylinders. To wit, such printing device allows applying at least three colors for the first as well as for the second print pattern, wherein each cylinder then is responsible for performing one of these two print patterns in one of these three colors. Printing presses with six cylinders are available for certain applications at specialized printing firms.

In the case of oblong covered panels or floor panels, the portion of both printing cylinders which is applied for printing the motif of these panels preferably extends transversely to the axis of these printing cylinders, such that the motif concerned in said decorative print extends substantially parallel to the printing direction, i.e. performing "longitudinal printing". According to this preferred embodiment of the invention, it is obtained that the maximum obtainable length of a printed motif is not necessarily limited by the circumference of the printing cylinders or the width of the printing cylinders. Corresponding to the number of different print patterns and printing cylinders applied according to the invention for forming the decorative print, the maximum obtainable length can be chosen freely. However, already a considerable improvement in respect to the state of the art is achieved when employing two different print patterns.

The method of the invention can offer many advantages when being applied for manufacturing floor panels with a length that is larger than the length of said first print pattern or is larger than the length of said second print pattern. To wit, the invention allows, for example, in the case of longitudinal printing, performing printed motifs for these floor panels without repetitions of the print pattern, which up to date has been considered impossible by those skilled in the art, unless transverse printing was used. Preferably, the floor panels have a length situated between 1.2 and 1.7 times the length of the first print pattern. When both print patterns have approximately the same length, an interesting length can be achieved by means of floor panels having 1.5 times the length of the first print pattern, as then the printed motif of two floor panels can be realized by means of three print lengths. These dimensions lead to an economic balance wherein a certain degree of repetition in the larger print is tolerated and still a considerably larger variety of printed motifs of floor panels is achieved. Herein, the printed motif of the floor panels themselves does not show any repetitions of a print pattern or portions thereof.

When the method is applied for manufacturing floor panels, the printed decor of these floor panels preferably is formed by means of at least a portion of a zone in which said first print pattern is absent, as well as by means of at least a portion of a zone in which said second print pattern is absent. To wit, this embodiment also allows forming long floor panels without repetitions in the print pattern.

Preferably, the method of the invention is applied for manufacturing floor panels with printed motifs representing a wood motif and more particularly depicting one plank per floor panel. Preferably, this relates to oblong rectangular floor panels with a length of more than 1.5 meters, for example, a length of 2 meters and more, and a width of 15 cm or more, for example, a width between 20 and 30 centimeters. In such panels, the wood motif, i.e. the wood nerves and the wood pores, preferably extend in the printed motif in the longitudinal direction of the floor panel. In the case of longitudinal printing, the wood motif then also extends in the print direction on the substrate concerned. Preferably, the printed motif of such floor panel comprises at least one of said transitions between the first and the second print patterns. Of course, this then preferably concerns one or more transitions, in which the motif of the larger print is performed uninterruptedly.

As also mentioned above, there are substantially two important possibilities for the substrate on which the decorative print is provided.

According to a first possibility, said substrate relates to a preferably flexible material sheet, such a paper sheet, which, for example, forms part of a wound material web, upon which said larger decorative print then, preferably uninterruptedly, is provided. Such material sheet or material web or a portion thereof then can be applied as a decor layer in a laminate floor panel. To this aim, for example, the DPL technique already mentioned above can be applied. Patent documents WO91/06728 and WO 2006/074831 give examples for decor paper sheets known from the state of the art.

According to a second possibility, said substrate relates to a board-shaped substrate on which said print is provided directly, whether or not with intermediate layers. This may relate, for example, to a wood-based board material, such as

MDF or HDF (Medium Density Fiberboard or High Density Fiberboard). Directly printing on wood-based board materials as such is known, for example, from

EP 1 862 304. For possible intermediate layers and preceding grinding treatments performed on the board-shaped substrate, reference is made to WO 2006/002917.

It is noted that the substrates on which the decorative print is performed preferably have a width which corresponds or approximately corresponds to the width of the applied printing cylinders, for example, a width of 1.5 to 3 meters. Of course, it is possible to install several printing cylinders in axial direction next to each other for forming the larger print. In such case, the substrate preferably has a width corresponding to the overall width of the printing cylinders installed next to each other.

Preferably, the method of the invention also comprises the step of providing a background print on the substrate concerned. Such background print preferably is a print of uniform or almost uniform color and may also be performed, however, not necessarily, by means of the rotary offset printing technique. This background print may be performed, for example, by means of only one printing cylinder, however, may also consist of a multicolor print, or as such may also be performed according to the technique of the invention by means of at least two printing cylinders.

The invention further also relates to a covered panel obtained by means of a method according to the invention. Preferably, the covered panel herein relates to a covered panel which is oblong and rectangular and comprises at least a basic panel and a top layer with a printed motif provided on this basic panel, wherein the length of the floor panel is larger than 1.5 meters and the printed motif is free from repetitions.

In case the invention is applied for manufacturing floor panels, this preferably relates to floor panels with which a floating floor covering can be composed. To this aim, the floor panels are provided with mechanical coupling means at least at two opposite edges, and preferably at all edges, said coupling means allowing that two of such floor panels can cooperate with each other, wherein a locking is created in a vertical direction perpendicular to the plane of the floor covering as well as in a horizontal direction in the plane of the floor covering and perpendicular to the coupled edge. Such mechanical coupling means are known as such, for example, from WO 97/47834.

Preferably, the method of the present invention also comprises a step wherein the surface of the covered panels is provided with a structure, wherein this structure preferably corresponds to the printed motifs of the covered panels. In such case, a so-called structure in register with the printed motifs is obtained. Such structure can be obtained, for example, with a DPL technique by means of a press device comprising a structured press element, more particularly a press plate. According to a particular embodiment, a larger decorative print is used which shows successive zones, wherein the print pattern over these successive zones does not repeat itself over a total length which approximately corresponds to a dimension of the aforementioned press element.

With the intention of better showing the characteristics of the invention, hereafter, as an example without any limitative character, several preferred embodiments are described, with reference to the accompanying drawings, wherein:

Figure 1 schematically represents several steps in a method according to the invention;

Figure 2 represents a view according to the arrow F2 represented in figure

1 ;

Figure 3 represents a floor panel obtained by means of a method according to the invention; and Figure 4, at a larger scale, represents a cross-section according to the line

IV-IV represented in figure 3. Figure 1 schematically represents a step in a method for manufacturing covered panels according to the present invention. Herein, this relates to a step in which by at least two printing cylinders 1 a decorative print 2 is formed on a substrate 3. In the example, herein the technique of rotary offset printing is applied, wherein so- called plate cylinders are applied as printing cylinders 1 , wherein the printing plate situated on the mantle surface of the cylinder 1 comprises the printing image of a print pattern 4-5 to be applied. Said printing image is formed in that the printing plate, on the one hand, comprises water-friendly portions and, on the other hand, comprises ink-friendly portions, wherein the print pattern 4-5 is formed by means of the ink-friendly portions. As figure 1 represents, ink from an ink container 7 or ductor is provided by means of ink rollers 6 on the plate cylinder or printing cylinder 1 , whereas the printing cylinder 1 is wetted from another reservoir 8 by means of wetting rollers 9. During each rotation, the printing cylinder 1 first moves along the wetting rollers 9, which wet the non-printing portions, for example, with water, thereafter the printing cylinder 1 moves along the ink rollers 6, which apply ink to the water-repellent portions of the printing cylinder 1 or printing plate.

In the represented case, the ink which is provided on the printing cylinder 1 is transferred to a transfer element 10, in this case, a rubber blanket cylinder, which transfers the print pattern 4-5 concerned onto the substrate 3.

It is noted that a possible drying installation for drying the formed print 2 is not represented here, however, that such drying preferably in each case is applied at least between two successive printing cylinders 1. A drying of the formed print 2 allows maintaining the register among the respective print patterns 4-5 provided by successive printing cylinders 1 in a better manner. This latter is certainly the case when a paper sheet or another porous underlying base is used as a substrate 3. A porous underlying base namely can show considerable stretching when such underlying base takes up the ink of the print 2 at least to a certain extent.

According to the invention, said decorative print 2 is composed at least of a first print pattern 4 and a second print pattern 5, at least provided by means of a first printing cylinder 1A and a second printing cylinder 1 B, respectively, of said two printing cylinders 1. In the example, the decorative print 2 is formed such that it shows at least a zone 11 in which said first print pattern 4 is absent, as well as shows at least a zone 12 in which said second print pattern 5 is absent. In the example, this relates to print patterns 4-5 of approximately the same length L, wherein this length is situated between 75% and 100% of the circumference of the printing cylinders 1A-1 B concerned.

In the example, asymmetric impression cylinders 13 are used, which reduce the pressure when the respective printing cylinder 1A-1B or rubber blanket roller 13 is inactive. Hereby, it can be obtained that the respective printing cylinder 1A-1B or rubber blanket roller 13 is relatively moved away from the substrate 3 at the right moments.

Figure 2 shows the aforementioned zones 11-12 of the larger print 2 in a clear manner. From this, it is clear that the zones 11 in which the first print pattern 4 is absent connect to a zone 12 in which the second print pattern 5 is absent. Moreover, the zones 11 in which the first print pattern 4 is absent are performed seamlessly with an adjacent zone 12 of the decorative print 2 in which this first print pattern 4 is present indeed. Such seamless embodiment or approximately seamless embodiment is represented in figure 2 by the dashed line 14. In this case, the decorative print 2 shows a wood motif extending uninterruptedly over the transition 15 of at least two zones 11-12. In this manner, a larger zone 16 with a continuous wood motif is formed, from which then, for example, long floor panels can be formed. In the example, this relates to the transition 15 in printing direction P, viewed from the first print pattern 4 towards the second print pattern 5. It is evident that the transition 17 in printing direction P, viewed from the second print pattern 5 towards the first print pattern 4, can be realized in a similar manner, however, this is not represented here. In such case, a so-called endless print 2 might be realized.

Figure 2 relates to so-called longitudinal printing, wherein the portions 18 of the decorative print 2, which are intended for use as a printed motif of one or more floor panels, extend in the printing direction P. As a substrate 3, use is made of a flexible material sheet, namely, a paper sheet. Preferably, said substrate 3 is made as a paper web, which is taken, for example, from a paper roll and, for example, is stocked again on a roll after finishing the printing process.

Figure 3 represents a floor panel 19 which is obtained by means of a method with the characteristics of the invention. It relates to a floor panel 19 which is oblong and rectangular. At least at two opposite edges 20-21 , and in this case at both pairs of opposite edges 20-21 and 22-23, the floor panel 19 is provided with coupling means 24 which allow that two of such floor panels 19 can be coupled to each other, wherein in the coupled condition at the respective edges 20-21 , 22-23 a mutual locking is obtained in a vertical direction V1 perpendicular to the plane of the coupled floor panels 19, as well as in a horizontal direction H1 perpendicular to the respective edge 20-21 , 22-23 and in the plane of the coupled floor panels 19. To this aim, said coupling means 24, as figure 4 shows, substantially are made as a tongue 25 and a groove 26, which, for the locking in horizontal direction H1, is provided with locking elements 27.

Figure 4 also shows that the floor panel 19 is a covered panel comprising a basic panel 28 and a top layer 29 provided on this basic panel 28. The top layer 29 as such comprises a decor layer 30 and a transparent or translucent protective layer 31 , such as a so-called overlay, which is provided over the decor layer 30. As is clear from figure 3, the decor layer 30 shows a printed motif 32 which is free from repetitions. The decor layer 30 is obtained as a portion 18 of the printed substrate 3, which is realized by means of the method of figure 2. Herein, the printed motif 32 of the floor panel 19 shows portions of the first print pattern 4 as well as portions of the second print pattern 5. The printed motif 18 also comprises a portion of the transition 15 between both print patterns 4-5. Thus, this relates to a floor panel 19 with a length L1 which is larger than the length L of each print pattern 4-5 present in the decorative print 2. It is noted that the floor panel 19 of the example is of the type showing a wood motif, wherein this wood motif more particularly depicts one plank per floor panel 19.

When the printed substrate 3 as such relates to a web-shaped substrate 3, such as a paper web, in the first place several decor sheets can be obtained therefrom, whether or not after such web-shaped substrate 3 has been subjected to a treatment, such as a treatment by which resin is provided on the substrate 3. By means of the DPL or HPL technique, such resin-provided decor sheet, together with a possible protective layer, which also may comprise a material sheet provided with resin, is provided on a larger basic board, which covered basic board then can be divided into panels having approximately the size of the final floor panels 19. The thus obtained covered panels then can be subjected to still further treatments, such as edge treatments for forming said coupling means 24. As a basic board or basic panel, then a board, panel, respectively, on the basis of wood and/or synthetic material can be applied, such as a MDF or HDF board, panel, respectively.

It is noted that the floor panel 19 of figure 4 also comprises a backing layer 33 or balancing layer, which is provided at the underside of the basic panel 28. For such backing layer 33 or balancing layer, also a material sheet provided with resin, such as a paper sheet, can be applied.

When material sheets provided with resin are mentioned, then, for example, a thermo-hardening resin, such as melamine resin, can be applied as the resin.

It is clear that, although above a first printing cylinder 1A and a second printing cylinder 1B, as well as a first print pattern 4 and a second print pattern 5 are mentioned, the invention is not limited to the specific sequence of the printing cylinders 1-1A-1B and/or print patterns 4-5 concerned, nor to a possible direct succession of the printing cylinders 1-1A-1B and/or print patterns 4-5 concerned. Indeed, according to the invention it is possible that one or more print patterns 4-5 are formed on the substrate 3 by means of one or more intermediate or preceding printing steps, whether or not by means of printing cylinders, and/or that the first printing cylinder 1A is situated in printing direction after the second printing cylinder 1B.

The present invention is in no way limited to the herein above-described embodiments, on the contrary may such methods and covered panels according to the invention be realized according to various variants, without leaving the scope of the present invention.

Claims

Claims.

1.- Method for manufacturing covered panels, wherein these covered panels (19) comprise at least a basic panel (28) and a top layer (29) with a printed motif (32) provided on this basic panel (28), wherein the method comprises at least the steps of forming a decorative print (2) on a substrate (3) by means of at least two printing cylinders (1A-1B) and of forming said covered panel (19) by means of at least a portion (18) of said substrate (3), characterized in that said decorative print (2) is composed at least of a first print pattern (4) and a second print pattern (5) at least provided by means of a first (1A) and a second (1B), respectively, of said two printing cylinders (1), and that the decorative print (2) is formed such that it comprises at least a zone (11) in which said first print pattern (4) is absent, whereas said second print pattern (5) in its turn is present in the zone (11) concerned.

2.- Method according to claim 1 , characterized in that the decorative print (2) is formed such that it comprises at least a zone (12) in which said second print pattern (5) is absent, whereas said first print pattern (4) in its turn is present in the zone concerned.

3.- Method according to claim 2, characterized in that the zones (11) in which the first print pattern (4) is absent, connects, whether or not by means of a transition portion (15), to a zone (12) in which the second print pattern (5) is absent.

4.- Method according to any of the preceding claims, characterized in that the zones (11) in which the first print pattern (4) is absent, are made seamless in respect to an adjacent zone (12) of the decorative print (2), in which this first print pattern (4) in its turn is present.

5.- Method according to claim 4, characterized in that said larger print (2) is uninterrupted in the printing direction (P).

6.- Method according to any of the preceding claims, characterized in that said two printing cylinders (1A-1 B) in the printing direction (P) are rolled off at least over a portion of their mantle surface, whether or not directly, over the substrate and wherein the length (L) of the respective print patterns (4-5) extends in the printing direction (P).

7.- Method according to any of the preceding claims, characterized in that for forming said zone (11) in which the first print pattern (4) is absent, the printing cylinder (1A) concerned is moved away from the substrate (3), or vice versa.

8.- Method according to any of the preceding claims, characterized in that for forming said zone (11) in which the first print pattern (4) is absent, the printing cylinder (1A) concerned has an active printing surface which is smaller than its mantle surface.

9.- Method according to any of the preceding claims, characterized in that for printing the substrate (3), the technique of so-called rotary offset printing is applied.

10.- Method according to any of the preceding claims, characterized in that for printing the substrate (3), a printing device is used having at least four cylinders (1), wherein, as aforementioned, at least one of these four cylinders (1) effects a discontinuous print pattern (4) on the substrate (3).

11.- Method according to any of the preceding claims, characterized in that the portion of the printing cylinders (1A-1B) which is used for printing the motif (32) of a floor panel (19), extends substantially transverse to the axis of this printing cylinder (1A-1B), such that the motif (32) concerned, in said decorative print (2), extends parallel to the printing direction (P).

12.- Method according to any of the preceding claims, characterized in that it is applied for manufacturing floor panels (19) with a length (L1) which is larger than the length (L) of said first print pattern (4) and/or is larger than the length (L) of said second print pattern (5).

13.- Method according to any of the preceding claims, characterized in that it is applied for manufacturing floor panels (19), the printed motif (32) of which is formed by means of at least a portion of a zone (11 ) in which said first print pattern

(4) is absent, as well as by means of at least a portion of a zone (12) in which said second print pattern (5) is absent.

14.- Method according to any of the preceding claims, characterized in that it is applied for manufacturing floor panels (19) with printed motifs (32) representing a wood motif and more particularly depicting one plank per floor panel (19).

15.- Method according to any of the preceding claims, characterized in that said substrate (3) relates to a flexible material sheet, such as a paper sheet.

16.- Method according to any of the preceding claims, characterized in that said substrate (3) relates to a board-shaped substrate which comprises at least one of said basic boards and wherein the print (2), whether or not by means of intermediate layers, is formed directly on the substrate (3).

17.- Covered panel, obtained by means of a method according to any of the preceding claims, characterized in that this covered panel (19) is oblong and rectangular and comprises at least a basic panel (28) and a top layer (29) with a printed motif (32) provided on this basic panel (28), wherein the length (L1) of the floor panel (19) is larger than 1.5 meters and the printed motif (32) is free from repetitions.