U.S. patent application number 09/867903 was filed with the patent office on 2001-12-06 for process and device for the positioning of printed images on package troughs.
Invention is credited to Michel, Frank, Schmidt, Hermann.
Application Number | 20010047638 09/867903 |
Document ID | / |
Family ID | 7644268 |
Filed Date | 2001-12-06 |
United States Patent
Application |
20010047638 |
Kind Code |
A1 |
Schmidt, Hermann ; et
al. |
December 6, 2001 |
Process and device for the positioning of printed images on package
troughs
Abstract
The present invention relates to a process and device for the
cyclic positioning of images over package troughs, said images
being printed on a covering film.
Inventors: |
Schmidt, Hermann; (Bad
Laasphe, DE) ; Michel, Frank; (Steffenberg,
DE) |
Correspondence
Address: |
PERMAN & GREEN
425 POST ROAD
FAIRFIELD
CT
06430
US
|
Family ID: |
7644268 |
Appl. No.: |
09/867903 |
Filed: |
May 30, 2001 |
Current U.S.
Class: |
53/51 |
Current CPC
Class: |
B65B 41/18 20130101 |
Class at
Publication: |
53/51 |
International
Class: |
B65B 057/02 |
Foreign Application Data
Date |
Code |
Application Number |
Jun 2, 2000 |
DE |
10027048.4 |
Claims
1. A process for the cyclic precise positioning of printed images
(3) over package troughs (4), said images (3) being printed on a
covering film (1) at a certain distance apart to retain an
unprinted strip (2), using a device (10) which consists of a first
and a second photoelectric cell (5, 6) and a film brake (7)
arranged between the photoelectric cells (5, 6), the covering film
(1) being sealed after positioning on the package trough (4) and
the package (8) thus obtained and hence the covering film (1) being
fed onward afterwards by a defined distance, wherein at each
stoppage of the film, preferably during sealing, it is ascertained
whether the second photoelectric cell (6) detects a strip (2) and
upon detecting a strip the first photoelectric cell (5) is
activated, during the onward feed of the covering film (1), the
first photoelectric cell (5) triggers the film brake (7) as soon as
it has detected a strip (2) between two passing images (3), so that
the onward feed of the covering film (1) is stopped at the position
of the film brake (7) and the covering film (1) is stretched as a
result of the ongoing forward feed of the package (8) last
sealed.
2. The process according to claim 1, characterized in that the
first photoelectric cell (5) is displaced along the x axis in order
to change the time of strip (2) detection.
3. The process according to claim 1 or 2, characterized in that a
printing mark (9), which is used for the positioning of the images
(3), is printed on the strip (2).
4. A device (10) for the cyclic precise positioning of printed
images (3) over package troughs (4), said images (3) being printed
on a covering film (1), using a first and a second photoelectric
cell (5, 6) and a film brake (7) arranged between the photoelectric
cells (5, 6).
5. The device according to claim 4, characterized in that the
second photoelectric cell (6) detects the position of the strip (2)
and/or printing mark (9) at each stoppage of the covering film (1)
and, depending on this, optionally activates the first
photoelectric cell (5) which in turn, if activated, triggers the
film brake (7) as soon as it has detected a strip (2) and/or
printing mark (9) between two passing images (3).
6. The device according to claim 4 or 5, characterized in that the
second photoelectric cell (6) is preferably arranged immediately
upstream of the sealing device (11).
7. The device according to any of claims 4 to 6, characterized in
that the first photoelectric cell (5) is pivotable about the z axis
in order to change the time of detection of a strip (2) and/or
printing mark (9).
8. The device according to any of claims 4 to 7, characterized in
that detection hysteresis of at least the second photoelectric cell
(6) is <0.4 mm, preferably <0.25 mm and especially preferably
<0.15 mm.
9. The device according to any of claims 4 to 8, characterized in
that the device is controlled by an SPC.
10. A film brake having three rolls (12 to 14) and two braking
means (15, 16) which cooperate with the rolls (12, 14), the rolls
(12, 14) having a different direction of rotation than the roll
(13).
11. The film brake according to claim 10, characterized in that the
roll (13) has a displaceable bearing.
12. The film brake according to claim 10 or 11, characterized in
that the braking means (15, 16) are driven pneumatically or
electrically.
13. The film brake according to any of claims 10 to 12,
characterized in that the film brake is activated by the first
photoelectric cell (5).
Description
[0001] The present invention relates to a process and device for
the cyclic positioning of images over package troughs, said images
being printed on a covering film.
[0002] Packages, particularly food packages, are becoming
increasingly important today. These packages often consist of a
package trough, in which the product to be packaged, for example
food, is filled and onto which a covering film is sealed so that
the product to be packaged is closed air-tight. To seal the package
troughs, they are fed cyclically by a servo chain drive system into
the so-called sealing station, the covering film is sealed onto the
package trough and the finished package is then fed onward by the
servo chain drive system. As the covering film after sealing is
permanently joined to the package trough, the covering film is
unrolled cyclically from a roll during the onward feed of the
finished package.
[0003] Employed increasingly today as the covering films are films
printed with images which cover almost the entire cross-section of
the package trough so as to make packages more appealing. As the
images are almost the same size as the package trough onto which
they are sealed, the images have to be positioned with a tolerance
of .+-.0.5 mm. This proved to be impracticable in the past because,
for instance, of the constant change in the filling level of the
package troughs and thus in the required length of covering film as
well as in the expansion behaviour of the film as a function of
temperature or humidity.
[0004] The object is therefore to provide a process and a device by
means of which images printed onto covering films can be precisely
positioned over package troughs.
[0005] According to the invention, said object is achieved by a
process for the cyclic precise positioning of printed images over
package troughs, said images being printed on a covering film at a
certain distance apart to retain an unprinted strip, using a device
which consists of a first and a second photoelectric cell and a
film brake arranged between the photoelectric cells, the covering
film being sealed after positioning on the package trough, and the
package thus obtained and hence the covering film being fed onward
afterwards by a defined distance, wherein
[0006] at each stoppage of the film, preferably during sealing, it
is ascertained whether the second photoelectric cell detects a
strip and upon detecting a strip the first photoelectric cell is
activated,
[0007] during the onward feed of the covering film, the first
photoelectric cell triggers the film brake as soon as it has
detected a strip between two passing images, so that the onward
feed of the covering film is stopped at the position of the film
brake and the covering film is stretched as a result of the ongoing
forward feed of the package last sealed.
[0008] The covering film is any desired covering film known to the
person skilled in the art, which is unrolled from a roll and
printed with images. An image in the meaning of the invention is
any desired printable representation of, for example, products,
advertising slogans and/or company logos. The images are arranged
at a certain distance apart so that there is always an unprinted
strip between any two images. For the process according to the
invention, only the unprinted strips which extend transversely to
the direction of running of the covering film are relevant.
[0009] The covering film is sealed in the sealing station onto
package troughs filled with product to be packaged. To this end the
package troughs are fed cyclically, e.g. by a servo chain drive,
into the sealing station, the covering film is sealed onto the
package trough and the package thus obtained is fed onward by the
servo chain drive by a precisely defined distance so that the
subsequent package troughs can then be sealed. As the covering film
is permanently joined to the package trough, the covering film is
forcibly unrolled from the roll when the finished package is fed
onward. A person skilled in the art will understand that this
unrolling takes place cyclically.
[0010] After sealing, the packages are cut apart in a cutting
station.
[0011] According to the invention, the images are precisely
positioned over the package troughs with the aid of a first and a
second photoelectric cell and with a film brake which is arranged
between the two photoelectric cells. In relation to the direction
of covering film running, the second photoelectric cell is situated
downstream of the film brake. At each stoppage of the covering
film, preferably during the sealing of the covering film onto the
package trough, the second photoelectric cell checks whether it can
detect a strip aligned at right angles to the direction of film
running and located between two images. If this is the case, the
printed images have run forward and the first photoelectric cell is
activated so that it in turn can trigger the film brake as soon as
the first photoelectric cell has detected a strip between two
passing images.
[0012] The film brake can be any film brake known to a person
skilled in the art.
[0013] As a result of braking during onward feed, the covering film
is stretched between the film brake and the package last sealed,
with the result that the position of the image which is to be
sealed next onto a package trough is set back in relation to the
direction of running of the covering film. This process is repeated
at each cycle and until the second photoelectric cell fails to
detect a strip and resumed as soon as the second photoelectric cell
detects another strip.
[0014] The point in time for the activation of the first
photoelectric cell is freely selectable, although activation should
take place when the covering film is already being fed onward, i.e.
during the next cycle. The first photoelectric cell is preferably
activated shortly before completion of the forward feed of the
finished packages and that of the covering film. Activation takes
place preferably 40 to 100 mm and especially preferably 50 to 80 mm
before completion of the forward feed of the covering film.
[0015] In a preferred embodiment of the device according to the
invention, the first photoelectric cell is displaceable along the x
axis (see FIG. 3). As a result of this displacement, it is possible
to change the time of strip detection. If the photoelectric cell is
displaced in the direction opposite to that of film running, the
time of strip detection is brought forward, with the result that
the covering film after actuation of the film brake is stretched
more because the remaining forward feed of the covering film is
longer. If the photoelectric cell is displaced in the same
direction as that of film running, the time of strip detection is
delayed and the covering film is consequently stretched less after
actuation of the film brake.
[0016] In a preferred embodiment, printing marks are printed on the
covering film between any two images. These marks are then used
instead of the strips for the positioning of the images.
Positioning is then performed by analogy with strip
positioning.
[0017] The advantage of the process according to the invention is
that images can be positioned on covering films very simply and
with great precision with a deviation of .ltoreq.0.5 mm. The
process can be performed with very little effort and has proven to
be extremely rugged. In spite of film changes and machine
stoppages, trouble-free use of the process according to the
invention has been possible over a very long period.
[0018] The present invention is also directed to a device for the
cyclic precise positioning of images printed onto a covering film
over package troughs, using a first and a second photoelectric cell
and a film brake arranged between the two photoelectric cells.
[0019] The film brake can be any film brake known to a person
skilled in the art.
[0020] In relation to the direction of covering film running, the
second photoelectric cell is situated downstream of the film brake.
In relation to the direction of film running, the second
photoelectric cell is preferably arranged immediately upstream of
the sealing device or downstream of the sealing device.
[0021] In a preferred embodiment, the second photoelectric cell
detects the position of a strip and/or printing mark at each
stoppage of the covering film, preferably during sealing, and,
depending thereon, optionally activates the first photoelectric
cell which in turn, if activated, triggers the film brake as soon
as it has detected a strip and/or printing mark between two passing
images.
[0022] The point in time for the activation of the first
photoelectric cell is freely selectable, although activation should
take place when the covering film is already being fed onward, i.e.
during the next cycle. The first photoelectric cell is preferably
activated shortly before completion of the forward feed of the
finished packages and that of the covering film. Activation takes
place preferably 40 to 100 mm and especially preferably 50 to 80 mm
before completion of the forward feed of the covering film.
[0023] In a preferred embodiment of the process according to the
invention, the first photoelectric cell is displaceable along the x
axis (see FIG. 3). As a result of this displacement, it is possible
to change the time of strip detection. If the photoelectric cell is
displaced in the direction opposite to that of film running, the
time of strip detection is brought forward, with the result that
the covering film after actuation of the film brake is stretched
more because the remaining forward feed of the covering film is
longer. If the photoelectric cell is displaced in the same
direction as that of film running, the time of strip detection is
delayed and the covering film is consequently stretched less after
actuation of the film brake.
[0024] The detection hysteresis of the second photoelectric cell,
though especially preferably of both photoelectric cells, is
preferably <0.4 mm, highly preferably <0.25 mm and especially
preferably <0.15, measured at a standard distance of 9.5 mm
between the lens and film.
[0025] The device according to the invention is advantageously
controlled by a stored programme control (SPC). Equally preferred
is control by a personal computer or microprocessor.
[0026] The advantage of the device according to the invention is
that images can be positioned on covering films very simply and
with great precision with a deviation of <0.5 mm. The device is
very easy to construct and has proven to be extremely rugged. In
spite of film changes and machine stoppages, trouble-free use of
the device according to the invention has been possible over a very
long period.
[0027] The present invention is also directed to a film brake with
three rolls about which the film runs and two braking means. In
relation to the direction of film running, the rolls are arranged
in sequence, the middle having a different direction of rotation
than the two outer rolls. The two outer rolls preferably cooperate
with the two braking means. The middle roll preferably has a
displaceable bearing.
[0028] The braking means are preferably driven pneumatically or
electrically.
[0029] In a preferred embodiment, the film brake according to the
invention is activated by the first photoelectric cell of the
device according to the invention to position images on package
troughs.
[0030] The film brake according to the invention is simple and
inexpensive to produce. The film brake has a very short response
time. Any slipping of the film through the film brake is excluded.
The film brake according to the invention was found to be extremely
rugged.
[0031] The invention is explained in the following with reference
to FIGS. 1 to 4. This is merely an explanation by way of example
and does not limit the general idea of the invention.
[0032] FIG. 1 shows a covering film which is printed with
images.
[0033] FIG. 2 shows a covering film printed with images and having
additional printing marks.
[0034] FIG. 3 shows a sealing station with the positioning device
according to the invention.
[0035] FIG. 4 shows the film brake according to the invention.
[0036] FIG. 1 shows a covering film 1 onto which the images 3 are
printed. The images 3 are printed at a certain distance apart on
the covering film, thus yielding strips 2 at right angles to the
direction of film running (indicated by the arrow). The strips
oriented in the same direction as film running are irrelevant to
the present invention.
[0037] The covering film according to FIG. 2 is essentially the
same as the covering film according to FIG. 1, the covering film
according to FIG. 2 having printing marks in addition.
[0038] FIG. 3 shows a sealing station with the positioning device
according to the invention. The package troughs 4 filled with
product to be packaged are fed cyclically by a servo chain drive
into the sealing station where they are sealed in the sealing
device 11 with a covering film 1. After sealing, the finished
packages 8 are fed onward by the servo chain drive to a cutting
station (not illustrated) cyclically, in each case by a defined
distance. The covering film 1 is cyclically unrolled from the roll
17 as a result of the onward feed of the packages 8.
[0039] The positioning device according to the invention consists
of a first and a second photoelectric cell (5, 6) and of a film
brake 7 arranged between the photoelectric cells. In relation to
the direction of running of the covering film, the second
photoelectric cell 6 is immediately upstream of the sealing device
11. The covering film runs with the printed side directly past the
photoelectric cells 5, 6 and wraps itself partly around the rolls
of film brake 7. The photoelectric cells 5, 6 are products of
Visolux Elektronik GmbH, Prinzenstr. 85, 10969 Berlin and have a
detection hysteresis of 0.1 mm, measured at a distance of 9.5 mm
between the lens and film. The positioning according to the
invention is controlled by an SPC.
[0040] During sealing, the SPC inquires whether the second
photoelectric cell 6 detects a strip 2 or a printing mark 9. If
this is the case, the system knows that the image has run forward.
During the next onward feed of the covering film 1 and 60 to 70 mm
before completion of the forward feed of the sealed packages 8 and
thus of the covering film, the photoelectric cell 5 is activated by
the SPC. The first photoelectric cell 5 in turn activates the film
brake 7 as soon as it has detected a strip 2 or a printing mark 9
between two passing images 3. The onward feed of the covering film
1 is stopped abruptly by the film brake 7 at the brake's position,
while the forward feed of the packages 8 still continues briefly,
causing the covering film 1 to be stretched between the package 8
last sealed and the film brake 7. Consequently, the images are
pulled back somewhat in relation to the direction of running of the
covering film 1. This process is repeated until the second
photoelectric cell 6 fails to detect a strip 2 or printing mark 9
during the stoppage of the covering film 1. If the second
photoelectric cell 6 does not detect a strip 2 or printing mark 9,
the first photoelectric cell 5 and thus the film brake are not
activated during the next cycle.
[0041] FIG. 4 shows the film brake 7 according to the invention
with three rolls 12-14 and two brake discs 15 and 16 which interact
with the rolls 12 and 14. The roll 13 has a displaceable bearing,
so that the angle of wrap of the covering film on the rolls can be
adjusted. The brake discs are driven by two pneumatic cylinders.
The film brake according to the invention is activated by the first
photoelectric cell 5.
* * * * *