EP3457388B1 - Self-adhesive label roll - Google Patents

Description

The invention relates to a roll of self-adhesive labels in the form of a printable, continuous strip without a liner, from which individual self-adhesive labels can be separated, the continuous strip having a printable front-side surface of the strip and an opposite rear-side surface of the strip with an adhesive layer, so that the continuous strip can be wound into a roll, wherein the endless strip is designed so that self-adhesive labels can be torn off at tear or cut lines transverse to the longitudinal direction of the endless strip, the tear or cut lines on the back of the strip being surrounded by an adhesive layer-free area, and on the back of the strip surface from outside Detectable markings are attached to the continuous strip, which indicate the position of the areas free of the adhesive layer and the detection of which enables automatic control of the process of separating the adhesive labels from the continuous strip touch allows.

Such a self-adhesive label roll with detectable markings (so-called "black marks") is known from US Pat US 6,585,437 B1 . This known self-adhesive label roll corresponds to the preamble of claim 1.

Such self-adhesive label rolls make it possible, for example, to print different current data, in particular product data, on a large number of labels by means of a printer.

The respective label can be peeled off the roll and stuck individually to a desired surface. This can be done in the simplest case done by hand, such as in the EP 1 053 289 B2 is described. A printable, linerless, continuous strip is also assumed there, from which individual self-adhesive labels can be separated. For better manual handling of the individual adhesive coupons, it is proposed to provide adhesive-free areas in the adhesive layer on the back of the tape, where the tape can be touched without the user's fingers coming into contact with the adhesive.

The EP 3 021 307 A1 proposes the provision of notches on the edges of the tape, each marking the beginning and the end of a separation area between two labels following one another on the tape.

While traditional adhesive labels consist of paper, glue and a carrier tape (English "liner"), the more modern linerless technology dispenses with the carrier material. Instead of the extensive carrier tape, the paper of the linerless labels is coated with a special surface substance, for example with a silicone layer, through which the labels can be rolled up in layers and detached from one another. By dispensing with the carrier material, the linerless quality gives you significantly more printable area per label roll.

The US 6,358,353 B1 describes a roll of labels. There are markings with fluorescent ink between the labels, which convert UV light into visible light. When the label roll is irradiated with modulated UV light, the markings emit the UV light as visible light. This converted light is measured by a detector. A cutting device cuts off the labels at the points indicated in this way by the markings.

The US 2014/0152753 A1 discloses a label sheet. The label sheet can be printed with heat on the printing surface on the front. There are markings on the back of the label sheet. The markings indicate the position of the printing surfaces and can be detected by an optical sensor. A printer identifies the information encoded in the markings and carries out a corresponding printing on the printing surfaces in order to produce the labels.

In the case of the cited in the beginning US 6,585,437 B1 A linerless continuous strip is also used, on the back of which the surface of the strip is provided with detectable markings in recesses in the adhesive layer, which indicate the position of the adhesive layer-free areas and the detection of which is an automatic control of the process of separating the adhesive labels from the continuous strip Adhesive layer-free area should allow. Such markings, which are in the US 6,585,437 B1 "Indicator marks" are known to the person skilled in the art - as already indicated above - also under the term "black marks". Blackmarks are usually printed as black bars. The black spot can then be recognized from the outside using a suitable detector. For the type of detection are in the US 6,585,437 B1 various other possibilities are also given, each using visible light or infrared light.

In this context, the application / introduction of color pigments in the adhesive layer is also described.

A disadvantage of these solutions is the previously always necessary presence of blackmarks, which are mostly disruptive in terms of appearance and aesthetics, in the visible spectral range.

In the prior art, the black marks, which have a certain width, are used to indicate the cutting edge. However, the blackmarks do not disappear after cutting. That is, they are still visible on the label, especially at the edge where they can even be seen particularly easily if the label has already been stuck on and you are looking at it from above. Since the blackmarks are arranged in the adhesive-free area, the label can easily be bent over at this point - barely noticeable - or detached from the product so that the black blackmark can be seen even more clearly. This would not be the case with an "invisible" black mark, but this is not possible with the prior art solutions.

The black black mark may also push through the label and can be seen as a shadow when looking at the label from the top. This is especially true when the label is stuck to a clear plastic tray and the tray may be backlit. In this case there would be scattered light underneath the label - from the inside of the plastic shell - and so the black blackmarks would shine through to the top of the label.

The object of the invention, on the other hand, is to improve a self-adhesive label roll of the type defined at the beginning inexpensively and with readily available technical means in an uncomplicated manner, in particular to offer a reproducible, manageable, operationally reliable and versatile self-adhesive label roll with an endless strip constructed without a liner, in which none for Blackmarks visible to the human eye are present.

This object is achieved in a technically particularly simple and surprisingly effective way by a generic self-adhesive label roll, in which the rear surface of the strip has an optical brightener contained in the strip material, integrated therein or applied to it, which has natural pigments and / or fluorescent components, and that the detectable Markings contain UV light absorbing, blocking or covering substances, so that a sensor sensitive to UV light receives a weakened UV light signal from the light reflected from the rear surface of the strip from the spatial surroundings of the markings.

Of course, the optical brightener is attached to the paper to reflect light on the front of the endless strip and thereby make the paper appear brighter and "whiter". As an unwanted and hitherto neglected side effect, the optical brightener in the paper also reflects on the back of the continuous strip, which the present invention makes use of. This effect has so far been disregarded, in particular, because in the processed state a self-adhesive label is stuck with the back on an object, and the back is therefore not visible. During the processing of the continuous strip, especially with linerless quality, the reverse side is However, the continuous strip is directly accessible and the reflection of light on the back of the continuous strip can be used for its processing. However, since the detectable markings cannot be seen even in the visible range of the spectrum, but rather only interact with the optical brightener in the UV range according to the invention, the presence of these "invisible" markings does not adversely affect the visual-aesthetic appearance of the label.

In this way, a convenient control of the cutting process of the individual self-adhesive labels is made possible. The endless strip itself is not necessarily controlled by the markings. These can be used to control the feed, but this does not necessarily have to be the case. However, the markings are used in any case for cutting off in the area free of the adhesive layer. The control of the feed happens more in connection with the printing process and the print roller.

As a rule, the strip material (paper) itself will have optical brighteners - at least in Europe and North America. The brighteners are usually not printed on separately, but rather "mixed in" with the paper material, that is to say part of the paper and thus integrated, so to speak. On the other hand, the optical properties of the fluorescent brightening substances, which at least in Europe and the USA are regularly integrated into the paper of the continuous strip or applied to it, are used in the proposals of the prior art for the external detection of the markings - namely in a non-visible spectral range - not used at all so far.

The term “surroundings of the marking” used above should be understood to mean that a light signal is weakened at the point where the marking is located, that is to say not only in the narrow sense directly around the marking.

The self-adhesive label roll according to the invention thus has a special type of detectable markings, in contrast to the previously customary design, which contain UV light absorbing, blocking or covering substances. These enable a sensor that is sensitive to UV light to receive a weakened UV light signal from the light reflected from the rear surface of the strip from the vicinity of the markings. Detection with sensors that react to UV light and work in the UV range at around 365nm makes it possible to use the optical brighteners that are used as standard in paper, at least in Europe and the USA, for the purpose of controlling the processing of the self-adhesive label roll close.

Explanations of the concept of optical brighteners

Optical brighteners are chemical substances, for example fluorescent substances, which are often used in photo papers (e.g. RC papers). They are integrated in the coating or in the paper base. Optical brighteners make the paper appear artificially whiter as a result.
The human eye can only perceive a very limited part of the electromagnetic spectrum of light. This part, the visible spectrum, lies between 380nm (ultraviolet limit) and 780nm (infrared limit). Optical brighteners are molecules that emit electromagnetic rays between 300nm and 400nm (i.e. outside the visible spectrum) and reflect them within the visible spectrum between 400nm and 500nm (in the range of the color blue). This phenomenon is known to those skilled in the art as fluorescence.

The natural cellulose fibers, which are omnipresent in paper production, tend to absorb radiation in the blue range and therefore appear yellowish. An optical brightener "compensates" for this loss in the spectrum, since the colors blue and yellow cancel each other out as complementary colors. In this way, the paper appears whiter and lighter thanks to the fluorescence effect.

In a particularly preferred embodiment of the self-adhesive label roll according to the invention, the optical brightener integrated in the strip material or applied to it has exclusively natural pigments and / or fluorescent components.

The adhesives usually used to build up the adhesive layer on the back of the continuous strip are practically always transparent or semi-transparent and do not cover the optical brighteners at all or only a little on the outside, so that the optical effect of the optical brightener on the Back of the continuous strip is present.

1. 1. Aufbringen im Haftschicht-freien Bereich.
2. 2. Aufbringen zwischen Klebstoff und Papier (also unter der Haftschicht) an der Stelle, an der der Klebstoff aufhört. Die Markierung befindet sich also unter dem Klebstoff und der Rand der Markierung ist bündig mit dem Rand der Haftschicht.
3. 3. Aufbringen an der gleichen Position wie bei 2., jedoch oberhalb des Klebstoffs aufgedruckt.
   Die Markierung überdeckt dann den Klebstoff, so dass der Klebstoff an dieser Stelle weniger oder nicht mehr klebt. Aufgrund der geringen Größe der Markierung, in einer bevorzugten Ausführungsform ca. 10mm x 5mm, vermindert das die Haftfähigkeit eines Etikettes kaum. Beim Aufdrucken der Markierung in der Mitte der Querseite des Endlosstreifens beeinträchtigt die Markierung auch nicht die Haftfähigkeit eines Etiketts an dessen Ecken.

In general, a distinction must be made between different options for applying a marking in the sense of the invention:

1. 1. Application in the area free of the adhesive layer.
2. 2. Application between adhesive and paper (i.e. under the adhesive layer) at the point where the adhesive ends. The marking is therefore under the adhesive and the edge of the marking is flush with the edge of the adhesive layer.
3. 3. Apply in the same position as in 2., but printed above the adhesive.
   The marking then covers the adhesive so that the adhesive sticks less or no longer at this point. Due to the small size of the marking, in a preferred embodiment approx. 10mm x 5mm, this reduces the Adhesion of a label hardly. When the marking is printed in the middle of the transverse side of the continuous strip, the marking also does not impair the adhesion of a label to its corners.

Accordingly, a distinction should be made between several classes of embodiments of the invention which, depending on the specific application, may have different advantages:
In a first class of embodiments, the substances covering the detectable markings or absorbing or blocking UV light are applied in the form of a white colored layer on the rear surface of the strip. This color layer can be printed in the same process and with the same production line as the black blackmarks known from the prior art. In the production process, the black color only needs to be replaced by white substances that absorb, cover or block UV light. The invention therefore only requires an uncomplicated conversion of the production system, but not its expansion, for example by a further printing station.

A second class of embodiments is characterized in that the substances covering the detectable markings or absorbing or blocking UV light are in the form of colored areas that act as UV absorbers between the rear surface of the strip and the adhesive of the adhesive layer or on the surface of the rear surface of the strip facing away from the outer surface of the adhesive layer are applied. In the first case, the adhesive is not covered by the marking and also in the area of the marking the detention effect of the detention view remains. In the second case, the previous production line for producing the label can be retained unchanged until the step of coating with adhesive. Up to this process step, there is no need to convert a production line that produces state-of-the-art labels. Only the part of the production line that implements the process step for applying the blackmarks needs to be modified in such a way that, after the adhesive layer has been applied, the detectable marking with the UV light absorbing, covering or blocking substance is printed in the form of a white ink layer.

In a third class of embodiments of the invention, the substances covering the detectable markings or absorbing or blocking UV light are applied in the form of color pigments that act as UV absorbers in the adhesive of the adhesive layer on the rear surface of the strip. In this case, the production line corresponds to a production line that does not print black marks, but can apply adhesive in certain structures (in English "pattern coating") in order to generate the areas on the label that are free of the adhesive layer. Instead of one of the previously common adhesives, however, an adhesive is used in which the color or the UV absorber is mixed. This means that the production line does not need to be retooled, just replacing the adhesive.

In particular, with advantageous developments of this class of embodiments, the self-adhesive label roll can be designed so that the color pigments contain inorganic substances such as titanium dioxide, indium oxide, calcium carbonate, in particular in finely ground and highly white or precipitated form, or iron pigments, but preferably none organic substances. The use of a large number of organic substances is prohibited, especially in the food sector, due to the strict hygiene regulations that apply there.

In practice, embodiments of the invention in which the adhesive of the adhesive layer is a hot-melt adhesive which can preferably be applied to the rear surface of the strip at 100 ° C. to 170 ° C. have proven successful. The melting point of the adhesive is usually between 90 ° C and 100 ° C. The processing temperature of the adhesive is usually around 140 ° C to 170 ° C.

Further processing is particularly simple in the case of embodiments of the self-adhesive label roll according to the invention in which the width of an individual label corresponds to the width of the continuous strip.

Alternative, somewhat more complex embodiments, which, however, open up more possibilities for variation for both the manufacturer and the user, are characterized in that the width of an individual label corresponds to the width of a fraction 1 / n of the continuous strip, where n is an integer and n ≥ 2 , and that in addition to the detectable markings in areas transverse to the longitudinal direction of the continuous strip, there are further detectable markings in areas parallel to the longitudinal direction of the continuous strip, so that a flat grid of detectable markings results on the rear surface of the strip.

However, this does not necessarily mean that the markings themselves form a check pattern, as is the case with checked paper, but they do can also only be applied in sections and thus indicate the points to be cut. In most cases, the markings will be applied in sections. Due to the fact that the black marks are invisible according to the invention, checked patterns that have been consistently avoided up to now are possible without the optical restrictions associated therewith in the prior art being created. The check pattern increases the universal applicability of the self-adhesive label roll, since the position of the sensor device for detecting the marking in the printer does not have to be coordinated with the label roll.

A marking should be at least 2mm x 2mm in size in order to be able to be reliably detected, whereby a more realistic size for process-reliable detection is 10mm x 5mm.

In this way, a single label, for example a postage stamp, can be cut off when the paper is narrow. In the case of wide paper, on the other hand, two or three labels can be arranged side by side, with the invisible black marks along the roll indicating the cutting position and further invisible black marks along the broad side of the roll showing the cutting position on this side. A grid of invisible blackmarks is then printed on. The invisible black marks along the broad side of the roll are also suitable for checking the alignment of the roll compared to a print head, especially if the printer does not have an exact lateral stop for the label roll and the labels do not have a predefined lateral position to the print head and / or take to a cutting device along the long side of the label roll.

Particularly important in practice are embodiments of the self-adhesive label roll according to the invention in which the adhesive labels are designed in a suitable manner for application to food, but also for use as postage stamps or as adhesive receipts for any labeling or labeling of goods. The advantages of the invention are particularly effective here.

Particularly when the adhesive labels are designed for use as postage stamps or as adhesive receipts, a combination with the features of the somewhat more complex embodiments described above proves to be favorable, in which n ≥ 2 labels and thus also n-1 detectable markings transverse to the longitudinal direction of the continuous strip are provided. In the case of shipping labels, several labels are often required at the same time, for example labels with a barcode associated with the shipment, one of which is attached to the top of the package, one to the side of the package and one on a delivery note for the package. These three labels with the same bar code can be printed and cut at the same time with the embodiment described with n = 3 labels.

• Bereitstellen eines Papiers mit optischem Aufheller und einer thermoreaktiven Schicht auf einer Vorderseite als Endlosstreifen für eine Selbstklebeetikettenrolle;
• optionales Aufdrucken einer Farbschicht über der thermoreaktiven Schicht auf der Vorderseite;
• optionales Silikonisieren der Vorderseite des Endlosstreifens;
• Aufdrucken von detektierbaren Markierungen, die UV-Licht absorbierende, blockierende beziehungsweise abdeckende Stoffe enthalten, auf der der Vorderseite gegenüberliegenden Rückseite des Endlosstreifens in Bereichen quer zu dessen Längsrichtung;
• Aufbringen einer Haftschicht auf die rückseitige Streifenoberfläche des Endlosstreifens derart, dass die Bereiche quer zur Längsrichtung des Endlosstreifens, in denen die detektierbaren Markierungen angebracht sind, frei von Klebstoff bleiben;
• Zuschneiden des Endlosstreifens in Längsrichtung auf seine gewünschte Breite;
• Aufrollen des Endlosstreifens zu einer Endlos-Selbstklebeetikettenrolle.

The scope of the present invention also includes a method for producing a self-adhesive label roll according to the invention of the type described above with the following steps:

• Providing a paper with an optical brightener and a thermoreactive layer on a front side as an endless strip for a roll of self-adhesive labels;
• optional printing of a color layer over the thermoreactive layer on the front side;
• optional siliconization of the front side of the continuous strip;
• Printing of detectable markings which contain UV light absorbing, blocking or covering substances on the rear side of the endless strip opposite the front side in areas transverse to its longitudinal direction;
• Applying an adhesive layer to the rear surface of the strip of the endless strip in such a way that the areas transverse to the longitudinal direction of the endless strip in which the detectable markings are applied remain free of adhesive;
• Cutting the continuous strip lengthwise to its desired width;
• Rolling up the continuous strip into a continuous self-adhesive label roll.

In the practical application of the invention, this process variant is likely to be the most common and most sensible method. However, it should be expressly pointed out that other, sometimes alternative, options are also conceivable with regard to the locations where the markings according to the invention can be printed.

An essential advantage is that the optical brightener - at least in Europe and North America - is already in the paper and can now be used in a simple way to detect the position of the labels. In addition, no optically disruptive black marks can be seen when using the present invention.
The method described above can advantageously be further developed in that the adhesive layer is applied to the rear surface of the strip by means of a printing process, preferably with a slot nozzle, a roller-bar nozzle and / or in one in a pattern coating process, so that an adhesive application is created with glue-free interruptions in order to later cut off the labels in this area.

Finally, the scope of the present invention also includes a method for processing a self-adhesive label roll according to the invention of the type described above, which is characterized in that the distance between two adjacent detectable markings in the longitudinal direction of the endless strip is a length X, and that the length of the of the self-adhesive label roll, labels currently to be cut is selected as a size N x X, where N is a natural number ≥ 1. The individual length N · X of the labels initially remains open and can, if required, also be set as an integer multiple of the distance X between the markings, so that when a label is cut an area without an adhesive layer is always hit by the knife. If the labels are cut off in the adhesive-free area, the knife wears significantly less and must first be replaced or cleaned at much longer maintenance intervals.

A particularly preferred variant of the processing method according to the invention is characterized in that the individual adhesive labels are printed on the front surface of the continuous strip with the aid of a printer, in particular by means of direct thermal printing, and are also cut by an integrated cutting device or a cutting device connected to the printer, precisely in the areas free of the adhesive layer.

The cutting device can in particular also comprise a rectangular cutter, which is transverse and longitudinal to the direction of the endless strip cuts at the same time and can therefore punch labels out of the roll very quickly and effectively.

This variant of the method can be further refined in that the printer has a sensor that is sensitive to UV light, which receives a light signal of the light reflected from the rear surface of the strip, that the sensor sends its received UV light signals to a control unit, and that the control unit, when it receives a weakened UV signal due to the current passing of a detectable marking, controls the printer and the cutting device in order to print an adhesive label and cut it off in an area free of adhesive layer, preferably along tear-off or cutting lines.

Further features and advantages of the invention emerge from the following detailed description of exemplary embodiments of the invention with reference to the figures of the drawing, which show details essential to the invention, and from the claims. The individual features can each be implemented individually or collectively in any combination in the case of variants of the invention.

In the schematic drawing, exemplary embodiments of the invention are shown, which are explained in more detail in the following description.

Fig. 1

eine perspektivische Darstellung einer ersten Ausführungsform der erfindungsgemäßen Selbstklebeetikettenrolle mit lediglich einem Klebeetikett pro Längenabschnitt des Endlosstreifens und mit jeweils in einem Haftschicht-freien Bereich angeordneten detektierbaren Markierungen;

Fig. 2A

eine schematische Draufsicht auf einen Abschnitt des Endlosstreifens in der Ausführungsform von Fig. 1;

Fig. 2B

eine schematische Draufsicht auf einen Abschnitt des Endlosstreifens in einer Ausführungsform ähnlich wie in Fig. 2A, jedoch mit Markierungen, die innerhalb des Bereichs der Haftschicht -darüber oder daruntersowie nicht an einem Rand, sondern in der Mitte des Endlosstreifens angeordnet sind;

Fig. 2C

eine schematische Draufsicht auf einen Abschnitt des Endlosstreifens in einer weiteren Ausführungsform mit mehreren nebeneinander angeordneten Klebeetiketten pro Längenabschnitt des Endlosstreifens und rasterartig verteilten Markierungen;

Fig. 3A

eine schematische Querschnittsansicht durch einen Abschnitt des Endlosstreifens in der Ausführungsform der Figuren 1 und 2A;

Fig. 3B

eine schematische Querschnittsansicht durch einen Abschnitt des Endlosstreifens in einer Ausführungsform mit den Markierungen am Rande der Haftschicht, aber im Haftschicht-freien Bereich;

Fig. 3C

eine schematische Querschnittsansicht durch einen Abschnitt des Endlosstreifens in einer Ausführungsform mit den Markierungen unterhalb der Haftschicht zwischen Papier und Haftschicht; und

Fig. 3D

eine schematische Querschnittsansicht durch einen Abschnitt des Endlosstreifens in einer Ausführungsform mit den Markierungen oberhalb der Haftschicht auf der Außenseite der rückseitigen Streifenoberfläche.

Show it:

Fig. 1

a perspective view of a first embodiment of the self-adhesive label roll according to the invention with only one Adhesive label per length section of the continuous strip and with detectable markings each arranged in an area free of adhesive layer;

Figure 2A

a schematic plan view of a portion of the endless strip in the embodiment of FIG Fig. 1 ;

Figure 2B

a schematic plan view of a portion of the endless strip in an embodiment similar to FIG Figure 2A , but with markings which are arranged within the area of the adhesive layer - above or below and not on an edge, but in the middle of the continuous strip;

Figure 2C

a schematic plan view of a section of the endless strip in a further embodiment with a plurality of adhesive labels arranged next to one another per length section of the endless strip and markings distributed in a grid-like manner;

Figure 3A

a schematic cross-sectional view through a portion of the endless strip in the embodiment of FIG Figures 1 and 2A ;

Figure 3B

a schematic cross-sectional view through a section of the endless strip in one embodiment with the markings at the edge of the adhesive layer, but in the area free of the adhesive layer;

Figure 3C

a schematic cross-sectional view through a portion of the endless strip in one embodiment with the markings below the adhesive layer between paper and adhesive layer; and

Figure 3D

a schematic cross-sectional view through a portion of the endless strip in one embodiment with the markings above the adhesive layer on the outside of the rear surface of the strip.

To make the invention easier to understand, the same reference numerals are used below for corresponding elements wherever possible, elements of alternative embodiments being marked with an apostrophe.

The invention is based on a self-adhesive label roll 1 in the form of a printable, continuous strip 2 constructed without a liner tape; 2 ', from which individual self- adhesive labels 3 can be separated, the endless strip 2; 2 'has a printable front-side strip surface 4 and a rear-side strip surface 5 opposite this, with an adhesive layer 6 , so that the endless strip 2; 2 'can be wound into a roll 1, the endless strip 2; 2 'is designed so that self-adhesive adhesive labels 3 on tear or cutting lines 7 transverse to the longitudinal direction of the endless strip 2; 2 'are separable, the tear or cutting lines 7; 7 ' on the back of the strip in each case from an area 8 free of adhesive layer; 8 'are surrounded, and wherein on the rear surface of the strip 5 from outside the endless strip 2; 2 ' detectable markings 9; 9 'are attached, which indicate the position of the areas 8; 8 'and their Detection enables automatic control of the separation process.

The self-adhesive label roll 1 according to the invention is distinguished from the prior art in that the rear-side strip surface 5 has an optical brightener contained in the strip material, integrated therein or applied to it, which reflects light incident on the rear-side strip surface 5 with increased proportions in the UV range, and that the detectable markings 9; 9 'contain UV light absorbing, blocking or covering substances, so that from the vicinity of the markings 9; 9 ′ a sensor sensitive to UV light receives an attenuated UV light signal of the light reflected from the rear surface 5 of the strip.

The Fig. 1 shows a first, relatively simple embodiment of a self-adhesive label roll 1 according to the invention, in which the width of an individual label corresponds to the width of the continuous strip 2 in a schematic spatial representation.

This embodiment is also shown in the schematic plan view of FIG Figure 2A as well as in the sectional view of Figure 3A shown.

In the Figures 1 , 2A , and 3A The detectable markings 9 shown were each selected to be positioned directly adjacent to a tear or cutting line 7. This positioning can, however, also be selected differently in other embodiments of the invention: a marking 9; 9 'also symmetrically on a tear-off or cutting line 7; 7 'or the adhesive layer-free Area 8; 8 'fill in completely or extend over the entire width of the label 3.

So shows Figure 2B an embodiment in which the markings 9 do not adjoin the tear or cutting lines 7, but are arranged in the area of the adhesive layer 6 at the edge of the adhesive-free area 8, between the paper surface and the - normally transparent- adhesive layer 6 or on them Exterior surface.

Figure 2C represents a somewhat more complex embodiment of the invention. Here the width of a single label corresponds to the width of a fraction 1 / n of the endless strip 2 ', where n is an integer and n ≥ 2, n = 3 in the specifically shown embodiment. In addition to the detectable markings 9 in adhesive-free areas 8 transversely to the longitudinal direction of the continuous strip 2 ', there are further detectable markings 9' in - also adhesive-free- areas 8 'parallel to the longitudinal direction of the continuous strip 2', so that there is a flat grid of detectable markings 9; 9 'on the rear strip surface 5 results.

The Figures 3A to 3D show schematically the respective cross section of the endless strip 2 with a selection of different possible embodiments. Common to all of these embodiments is the basic structural design of the endless strip 2, which has a thermoreactive layer 10 on the printable front surface 4 of the strip and a cover layer 11 (mostly a silicone layer) over it, which replaces the previously common liner.

As mentioned above, shows Figure 3A the embodiment according to Figures 1 and 2A .

Figure 3B shows a schematic cross-sectional view through a section of the endless strip 2 in an embodiment with markings 9 positioned on the edge of the adhesive layer 6, but in the adhesive-free area 8.

Figure 3C shows an embodiment with the markings 9 below the -transparent- adhesive layer 6 between paper and adhesive layer 6.

Figure 3D finally, shows an embodiment with the markings 9 above the adhesive layer 6 on the outside of the rear-side strip surface 5.

List of reference symbols

1

Self-adhesive label roll

2, 2 '

Endless strips

3

Adhesive label

4th

printable front strip surface

5

opposite back stripe surface

6th

Adhesive layer

7, 7 '

Tear or cut lines

8, 8 '

Adhesive-free areas

9, 9 '

detectable markings

10

thermoreactive layer

11

Cover layer

Claims (15)

1. Self-adhesive label roll (1) in the form of a printable, linerless continuous strip (2; 2') from which individual self-adhesive labels (3) can be detached, the continuous strip (2; 2') having a printable front strip surface (4) and a rear strip surface (5) opposite thereto having an adhesive layer (6), such that the continuous strip (2; 2') can be wound into a roll (1), the continuous strip (2; 2') being designed such that self-adhesive adhesive labels (3) can be detached at tear-off or cutting lines (7) transverse to the longitudinal direction of the continuous strip (2; 2'), the tear-off or cutting lines (7; 7') on the back of the strip each being surrounded by a region (8; 8') that is free of an adhesive layer, and markings (9; 9') which can be detected from outside the continuous strip (2; 2') being provided on the rear strip surface (5), which markings indicate the position of the regions (8; 8') free of an adhesive layer and the detection of which allows automatic control of the process of detaching the adhesive labels (3) from the continuous strip (2; 2'), characterized in that the rear strip surface (5) has an optical brightener contained in the strip material, integrated therein or applied thereto, which optical brightener has natural pigments and/or fluorescent components, and in that the detectable markings (9; 9') contain UV light absorbing, blocking or masking substances, such that a sensor sensitive to UV light receives, from the vicinity of the markings (9; 9'), a weakened UV light signal from the light reflected from the rear strip surface (5).
2. Self-adhesive label roll according to claim 1, characterized in that the optical brightener integrated in the strip material or applied thereto has exclusively natural pigments and/or fluorescent components.
3. Self-adhesive label roll according to either claim 1 or claim 2, characterized in that the substances masking the detectable markings (9; 9') or absorbing or blocking UV light are applied in the form of a white color layer on the rear strip surface (5).
4. Self-adhesive label roll according to either claim 1 or claim 2, characterized in that the substances masking the detectable markings (9; 9') or absorbing, blocking UV light are applied between the rear strip surface (5) and the adhesive of the adhesive layer (6) or on the outer surface of the adhesive layer (6) facing away from the rear strip surface (5) in the form of colored regions which act as UV absorbers.
5. Self-adhesive label roll according to either claim 1 or claim 2, characterized in that the substances masking the detectable markings (9; 9') or absorbing, blocking UV light are applied in the adhesive of the adhesive layer (6) on the rear strip surface (5) in the form of color pigments which act as UV absorbers.
6. Self-adhesive label roll according to claim 5, characterized in that the color pigments comprise inorganic substances such as titanium dioxide, indium oxide, calcium carbonate, in particular in finely ground and bright white or precipitated form, or iron pigments, but preferably do not comprise organic substances.
7. Self-adhesive label roll according to any of the preceding claims, characterized in that the adhesive of the adhesive layer (6) is a hot-melt adhesive which can be applied to the rear strip surface (5) preferably at 100°C to 170°C.
8. Self-adhesive label roll according to any of claims 1 to 7, characterized in that the width of an individual label (3) corresponds to the width of the continuous strip (2).
9. Self-adhesive label roll according to any of claims 1 to 7, characterized in that the width of an individual label corresponds to the width of a fraction 1/n of the continuous strip (2'), where n is an integer and n ≥ 2, and in that in addition to the detectable markings (9) in regions (8) transverse to the longitudinal direction of the continuous strip (2') there are further detectable markings (9') in regions (8') parallel to the longitudinal direction of the continuous strip (2'), resulting in a flat grid of detectable markings (9; 9') on the rear strip surface (5).
10. Self-adhesive label roll according to any of the preceding claims, characterized in that the adhesive labels (3) of the self-adhesive label roll are designed to be suitable for application to foodstuffs or for use as postage stamps or as adhesive receipts.
11. Method for producing a self-adhesive label roll according to any of claims 1 to 10, comprising the following steps:

    - providing paper having an optical brightener and a thermoreactive layer (10) on a front side (4) as a continuous strip (2) for a self-adhesive label roll;

    - optionally printing a color layer over the thermoreactive layer (10) on the front side (4);

    - optionally siliconizing the front side of the continuous strip (2);

    - printing detectable markings (9) containing UV light absorbing, blocking or masking substances on the rear side (5) of the continuous strip (2), opposite the front side (4), in regions (8) transverse to the longitudinal direction of said strip;

    - applying an adhesive layer (6) to the rear strip surface (5) of the continuous strip (2) such that the regions (8) transverse to the longitudinal direction of the continuous strip (2) in which the detectable markings (9) are applied remain free of adhesive;

    - cutting the continuous strip (2) in the longitudinal direction to the desired width;

    - rolling up the continuous strip (2) to form a "continuous" self-adhesive label roll.
12. Method according to claim 11, characterized in that the adhesive layer (6) is applied to the rear strip surface (5) of the continuous strip (2) by means of a printing process, preferably using a slot nozzle, a roll-bar nozzle and/or in a pattern coating process.
13. Method for processing a self-adhesive label roll according to any of claims 1 to 10, characterized in that the distance between two adjacent detectable markings (9) in the longitudinal direction of the continuous strip (2; 2') is in each case a length X, and in that the length of the labels currently to be cut from the self-adhesive label roll is selected as a size N·X, where N is a natural number ≥ 1.
14. Method according to claim 13, characterized in that the individual adhesive labels (3) are printed on the front strip surface (6) of the continuous strip (2; 2') by means of a printer, in particular by means of a direct thermal printing process, and can also be cut by means of a cutting device that is integrated or connected to the printer.
15. Method according to claim 14, characterized in that the printer has a to UV light, in particular in the UV-sensitive sensor, which receives a light signal from the light reflected from the rear strip surface (5) of the continuous strip (2; 2'), in that the sensor sends its received UV light signals to a control unit, and in that the control unit, when it receives a weakened UV signal due to the current passing of a detectable marking, triggers the printer and the cutting device in order to print an adhesive label (3) and to cut said label in a region (8; 8') free of the adhesive layer, preferably along tear-off or cutting lines (7; 7').

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