Material-web marking by means of bar code

The invention relates to a method and an apparatus for marking flat objects (4) by means of bar code (4). The object of the invention is to form a code, preferably a bar code, in that with the aid of an adhesive, for example, a thermoplastic adhesive, a two-component adhesive, an adhesive solution or the like, glass beads are applied to the objects in the form of a code, such glass beads having a diameter of 0.01 mm to 1 mm, preferably 0.05 mm to 0.8 mm, particularly 0.08 mm to 0.5 mm, and having a refractive index greater than 1.5, preferably 1.85 to 2.0.

BACKGROUND OF THE INVENTION 
The present invention relates to a method new and improved of applying 
codes to preferably flat objects, for example, textile webs, foils, 
fabrics, strips, window frames, profiled parts or the like. The invention 
also relates to an arrangement for performing this method. 
Such codes can serve, for example, for conducting the marked or coded 
objects or products during processing thereof to corresponding processing 
operations or storage locations. Regarding the objects, all those come in 
question which possess a surface or flat surface portion providing 
adequate space for applying a code marking, and which are movable past a 
marking or code forming arrangement. Preferably, mass-produced articles 
and assembly line articles are marked in such a manner. 
SUMMARY OF THE INVENTION 
With the foregoing in mind, it is a primary object of the present invention 
to provide a new and improved method of, and arrangement for, applying 
codes to an object and which method and arrangement are not afflicted with 
the drawbacks and limitations of the prior art. 
Another and highly significant object of the present invention is directed 
to the provision of a new and improved method of, and arrangement for, 
applying codes to an object and which method and arrangement result in 
highly durable and distinctly readable codes or code markings on such 
object. 
A further important object of the present invention aims at providing a new 
and improved method of, and arrangement for, applying codes to an object 
and which method and arrangement particularly permit applying to flat 
web-type objects code markings which are distinctly readable by means of a 
scanning or reading device during processing operations or on an assembly 
line carrying such flat or web-like objects. 
A still further important object is directed to providing a new and 
improved construction of a scanning arrangement for scanning codes or code 
markings and which scanning arrangement is particularly suited for 
scanning the codes or code markings which have been applied by carrying 
out the new and improved method using the new and improved arrangement for 
applying codes to an object. 
Now in order to implement these and still further objects of the invention, 
which will become more readily apparent as the description proceeds, the 
method of the present development is manifested, among other things, by 
the features that for forming a code, preferably a bar code, with the aid 
of a bonding agent, for example, a thermoplastic adhesive, a two-component 
adhesive, an adhesive solution or the like, glass beads are applied to the 
objects in the form of a code, such glass beads having a diameter of 0.01 
mm to 1.0 mm, preferably 0.05 mm to 0.8 mm, particularly 0.08 mm to 0.5 
mm, and having a refractive index greater than 1.5, preferably 1.85 to 
2.0. 
The arrangement for performing the method is characterized according to the 
invention in that the arrangement comprises an application or dispensing 
device for glass beads having a diameter of 0.01 mm to 1.0 mm, preferably 
0.05 mm to 0.8 mm, particularly 0.08 mm to 0.5 mm, and having a refractive 
index greater than 1.5, preferably 1.85 to 2.0. 
In this simple manner there is set up an arrangement of simple 
construction, by means of which a readily identifiable and accurately 
readable code can be applied, which code is attached by simple means and 
readily adheres to objects of varied surfaces. In particular, long 
material webs can be provided with such codes at a single or at several 
locations and then can readily be identified. With the arrangement 
according to the invention, it is rendered possible in simple manner to 
apply a code to a stationary or to a moving object. The glass spheres used 
for this purpose are readily detectable. The refractive index and the 
diameter are advantageously adapted or selected such that the focus of an 
electromagnetic scanning radiation, particularly light incident at the 
glass beads for detecting the code, is located within the glass spheres. 
It is possible, for example, that the adhesive or bonding agent is sprayed 
or pressed onto preselected surface areas of the object by using a mask 
for producing the code, or code markings, for instance, the bar code. The 
adhesive can also be scraped-on in the form of the code, for instance the 
bar code. The adhesive can be rubbed on without a mask by means of rubbing 
wheels, for instance, wheels or rubbing wheels corresponding to the width 
of the code markings, for example, of the bar code, or pressed on without 
a mask by means of dies. The glass beads are then applied to the adhesive 
spread, whereby the adhesive, for instance the bars of adhesive, is 
preferably entirely covered with the glass beads which, for example, are 
scattered or blown thereon. Glass beads not adhering to the bars of 
adhesive or bonding agent are removed, for example by being sucked or 
blown away. 
It is advantageous and simple when the glass beads are conveyed by a 
carrier which is moved relative to the object to be marked and when an 
area of the glass beads corresponding--in terms of form--to at least a 
portion of the desired code is pressed against the object to be marked by 
at least one pressing device, for instance a die and retained at the 
object by an adhesive carried by the latter and/or by the glass beads. In 
practice, the glass beads can be applied to, for instance, a band of 
plastic material of the carrier and secured thereat by the action of heat, 
or by means of adhesives or the like. The glass beads can be optionally 
coated with metal vapor and a layer of adhesive can be applied to the 
optionally metal-coated glass beads. 
It is advantageous when the glass beads applied to the adhesive are pressed 
by a pressure roller or the like. Adhesives which can be applied are 
thermoplastic adhesives, mixed adhesives, cold-setting adhesives and so 
forth. It is essential that the adhesive binds well with the object and 
the glass beads, and forms a durable compound or bond. 
The application of the adhesive to the objects can be effected in the form 
of the code, for instance the bar code, with the aid of the mask. Either a 
mask is provided for each code to be applied and is selected for the 
related case, or the mask is formed adjustable such that a plurality of 
codes can be formed with the mask and mask portions can be displaced or 
moved relative to one another in order to form an arrangement of recesses 
or apertures in the mask, such arrangement corresponding to the code. For 
forming a bar code, it is also possible to form always only one bar by 
means of an application device, the bars being applied to the object at 
corresponding intervals. Furthermore, the mask could be moved together 
with the object past the adhesive-application device; the object can also 
be stationary and the mask can be applied thereto, and the 
adhesive-application device can be moved relative to the mask. 
In an arrangement for reading codes, in particular bar codes, which are 
applied, in particular, to flat objects, such arrangement has an 
electromagnetic radiation source for irradiating the code, for instance an 
ultraviolet or infrared emitter, a light source or the like, and has a 
receiving or sensing device for the reflected radiation, for instance 
light. An evaluation unit is provided in accordance with the invention and 
comprises a discriminator circuit by means of which it is possible to 
suppress signals, which lie between the expected moments of time of 
arrival of signals produced by rays reflected by the code structured of 
glass beads, for instance infrared radiation or light or the like, or 
which signals do not attain a certain intensity and/or duration and are 
caused by glass beads lying on the material web at undesired locations, 
i.e. by glass beads adhering to the material web at locations beyond code 
areas or between bars. By virtue of such a device, the reception of 
signals and the detection of the code are ensured in a form perfectly 
suitable for evaluation. 
It is of particular advantage that the application of codes to the objects, 
particularly to those of considerable length, is possible during passing 
travel of the object. The application of the code as well as the reading 
of such code during passage under the optical sensor of the code reading 
device or arrangement in individual different processing operations or 
processing stages is readily possible. In particular, the momentary 
location of individual product groups can be determined and it is readily 
possible to centrally detect and control the flow of goods. 
The refractive index and the size and the material of the glass beads 
permit total reflection of the radiation or light radiated by the code 
reading arrangement or unit onto the code or code markings for reflection 
into the receiving device. Advantageously, the glass beads have diameters 
which correspond to a predetermined distribution curve.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Describing now the drawings, it is to be understood that only enough of the 
construction of the inventive arrangement has been shown as needed for 
those skilled in the art to readily understand the underlying principles 
and concepts of the present development, while simplifying the showing of 
the drawing. Turning attention now specifically to FIG. 1 of the drawings, 
the object 1 illustrated therein by way of example and not limitation will 
be seen to constitute a flat material web. It should be noted, however, 
that the object 1 can be constituted by any object having a flat surface 
portion 1A suitable for applying a code or code markings 31. Such objects 
1, may constitute flat objects like, for example, textile webs, foils, 
fabrics and strips as well as profiled parts such as, for instance, window 
frames. 
The object 1, in the first exemplary embodiment, constitutes a flat 
material web 1 which is moved according to FIG. 1 by conveying means 25 
conjointly with an applied mask 4, in which recesses or apertures are 
formed in conformity with a code, in the given instance a bar code, past 
code forming means 30 containing an adhesive application device 2 which 
sprays adhesive or bonding agent 14 onto the material web 1 through the 
recesses 22 in the mask 4. The adhesive 14 impacts only the region of the 
mask 4 and is applied to preselected surface areas 1B of a flat surface or 
surface portion 1A of the object or material web 1 in accordance with a 
desired code configuration; those areas of material web 1 located beyond 
the mask 4 are not impacted. After the application of adhesive has been 
carried out essentially in the form of the code, the material web 1 with 
the adhesive spread 3 is moved past a glass-bead dispensing device 11 by 
means of which glass beads 13 are poured, blown or scattered out of a 
container and onto the adhesive spread 3. A firm pressing of the glass 
beads 13 at the adhesive spread 3 can be effected by means of a pressure 
roller 15. During further travel of the material web 1 in the direction of 
the arrow 10, removal by blowing or sucking out the glass beads 13 not 
retained by the adhesive can be effected by a removal device 12, so that 
surplus glass beads do not cause any erroneous signals when the code or 
bar code is read. 
Subsequently, there is illustrated in the drawing the detection of the code 
or bar code applied to the material web 1, through the mask 4, by means of 
a code reading arrangement or unit 35. Radiation or visible light is 
radiating from a light emitter 5 onto the material web 1 and reflected by 
the glass beads 13 into a receiving or sensing device 6. The spacings 
between the code markings 31 or bars are selected to be preferably equal, 
the width of the bars being equal to the width or a multiple of the width 
of a predetermined selected bar width. The light receiver or sensing 
device 6 receives successive radiation or light pulses which produce 
output signals which are fed to an evaluation unit 8 via a discriminator 
circuit 7. The discriminator circuit or threshold-value circuit 7 serves 
for ensuring that glass beads 13 which are located between the individual 
code markings 31 or bars and were not removed and possibly guide or direct 
reflections of radiation or light to the receiver 6, are not let through 
to the evaluation unit 8. The evaluation unit 8 can possess a speed 
measuring device 9 for measuring the speed of the moved material web 1, in 
order to be able to check the sequence or the spacings of the bars and 
determine the timely arrival of the signals as a function of this speed. 
The evaluation unit 8 can further comprise a computer which, if necessary, 
can communicate with a central computer unit via a line 16 leading 
thereto, such central computer unit controlling the entire passage of 
goods. 
For the evaluation, it is also possible to proceed in such a manner that 
the signals received on the basis of those surfaces of the object limited 
by the glass beads, are evaluated as the signals corresponding to the 
code, which means that the code is not determined by the position of the 
glass beads, but by the spaces between the locations coated with the glass 
beads. The beginning of the code and the end of the code are thereby 
marked by a glass-bead code marking 31 or bar of a predetermined width. 
When the evaluation unit detects such a bar, it accepts in the sequel the 
lack of reflected radiation as code information and the arrival of 
reflected radiation as spacing between the code markings. The signals 
received from or associated with the dark scanned locations thus represent 
the code. 
Instead of a detection of the code or bar code by means of visible light, 
it is possible to use ultraviolet or infrared radiation or other 
electromagnetic radiations. To increase the reflection, there can be 
provided filling materials in the adhesive substance, such as aluminum 
tinsel, titanium dioxide TiO.sub.2 or similar brightening pigments or 
materials. 
It is preferred when glass beads or spheres provided with a reflective 
metal coating, for instance of aluminum, are applied to the adhesive and 
when, subsequent to the setting of the adhesive, the metal coating is 
removed, for instance by etching, from the exposed surfaces of the glass 
spheres. The metal layers remaining between the glass spheres and the 
adhesive substance act as mirror surfaces and present optimal surfaces of 
reflection. Etching away the metal coating in the case of textiles is 
preferably carried out during customary processing operations, for 
instance washing in lyes, which washing affects the metal coating. 
FIG. 2 shows a second exemplary embodiment of the inventive arrangement in 
which the glass beads 13 are supported by a carrier 17 which carries out a 
relative movement with respect to the object 1. The glass beads 13 can be 
applied to the carrier 17 by means of an adhesive 21 or, as FIG. 4 
depicts, pressed into the carrier 17 on a side 17A facing an object side 
1C of the object or material web 1. The glass beads 13 carry an adhesive 
layer 18 which, however, could also be carried by the object 1 or 
appropriately applied to the latter. By means of at least one die 19 
which--in terms of form--corresponds to a code or a code portion, glass 
beads 13 can be pressed onto the object 1 and separated from the carrier 
17. FIG. 3 shows two adjacent rows of glass beads 13 corresponding to the 
width of the die 19 which could correspond, for instance, to one bar of a 
bar code. In general, more than two rows of glass beads correspond to the 
minimum width of a bar. 
FIG. 4 shows a section through a modified version of the carrier 17 to 
which the glass beads 13 are attached by being pressed there into. The 
carrier 17 can be or may contain a thermoplastic band of plastic material 
into which heated glass beads 13 are pressed and adhere thereat. The 
reference numeral 20 designates a mirror or reflective coating of the 
glass beads 13 provided at the surface at which the glass beads are glued 
to the object 1. 
The adhesive 18 can be self-adhesive. If the adhesive 18 is thermosetting, 
the die 19 can be constructed to be heatable. If the adhesive 18 is 
ultraviolet-setting, the pressing surface of the adhesive can be 
transparent and structured for admission of ultraviolet radiation. The 
adhesive could also be soluble in water in order to be able to remove 
codes appled to textile materials during the manufacture thereof. 
The means for moving or feeding the object 1, the carrier 17 or the die 19 
are not illustrated. 
While there are shown and described present preferred embodiments of the 
invention, it is to be distinctly understood that the invention is not 
limited thereto, but may be otherwise variously embodied and practiced 
within the scope of the following claims.