U.S. patent application number 10/319790 was filed with the patent office on 2003-06-19 for method and apparatus for detecting product defects during the production of mailing products, hygiene products, or folded paper products.
This patent application is currently assigned to Winkler & Duennebier AG. Invention is credited to Saas, Dirk.
Application Number | 20030110739 10/319790 |
Document ID | / |
Family ID | 7709174 |
Filed Date | 2003-06-19 |
United States Patent
Application |
20030110739 |
Kind Code |
A1 |
Saas, Dirk |
June 19, 2003 |
Method and apparatus for detecting product defects during the
production of mailing products, hygiene products, or folded paper
products
Abstract
To detect product defects during the production of mailing
products, hygiene products or folded paper products, optical
imaging sensors or capacitive sensors monitor at least one
characteristic parameter or feature of the products successively
moving through the production machine, to detect an actual value of
each characteristic parameter or feature of each product. The
detected actual value is compared with a stored nominal value for
the respective characteristic parameter or feature. The result of
the comparison is used to initiate or control a further measure,
such as ejecting a defective product from the production line,
marking a defective product so that it can be visually recognized
and manually removed from the production line, or initiating
corrective measures to correct the cause of the defect. The
characteristic parameters or features relate to the dimensions, the
position, and/or the form of the product or parts of the
product.
Inventors: |
Saas, Dirk; (Winningen,
DE) |
Correspondence
Address: |
FASSE PATENT ATTORNEYS, P.A.
P.O. BOX 726
HAMPDEN
ME
04444-0726
US
|
Assignee: |
Winkler & Duennebier AG
Neuwied
DE
|
Family ID: |
7709174 |
Appl. No.: |
10/319790 |
Filed: |
December 13, 2002 |
Current U.S.
Class: |
53/460 |
Current CPC
Class: |
B31B 70/00 20170801;
B31B 70/006 20170801; B31B 2150/00 20170801; B31B 2160/10 20170801;
B31B 70/82 20170801 |
Class at
Publication: |
53/460 |
International
Class: |
B65B 011/48 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 13, 2001 |
DE |
101 61 424.1 |
Claims
What is claimed is:
1. A method for detecting product defects of products selected from
mailing products, hygiene products, and folded paper products,
during producing or packaging of said products, comprising the
steps: a) producing or packaging said products in a machine
including plural machine components; b) storing a respective
nominal value respectively for each one of at least one
characteristic parameter or characteristic feature of said
products, with respect to at least one of a dimension, a form, and
a position of said products or respective parts of said products;
c) during said producing or packaging of said products, detecting a
respective actual value of each said characteristic parameter or
characteristic feature of said products, respectively for each
individual one of said products; d) respectively comparing each
said actual value with said nominal value for each said respective
characteristic parameter or characteristic feature, to provide a
respective comparison result indicative of how said actual value
compares to said nominal value, for each said individual one of
said products; and e) in response to and dependent on said
comparison result, carrying out a further measure with respect to
any defective product among said products for which said comparison
result indicates that a defect exists.
2. The method according to claim 1, further comprising detecting a
plurality of said actual values with respect to a dimension, a
form, or a position of said product or of a part of said product,
relative to each other.
3. The method according to claim 1, used for detecting said product
defects of said mailing products during said producing of said
mailing products.
4. The method according to claim 1, wherein said further measure of
said step e) comprises at least one of indicating said comparison
result, carrying out a corrective measure for correcting said
defect, marking said defective product, documenting said comparison
result, and ejecting said defective product out of said
machine.
5. The method according to claim 1, wherein said detecting of said
actual value is carried out electrically or electronically, using
at least one of a line camera and a capacitive sensor.
6. The method according to claim 1, wherein said detecting of said
actual value is carried out using an optical sensor or a line
camera, and at least one mirror, so as to deflect an image beam of
an image of said characteristic parameter or characteristic feature
of said product via said at least one mirror to be received by said
optical sensor or said line camera.
7. The method according to claim 1, wherein said characteristic
parameter or characteristic feature of said product comprises at
least one of a size, dimensions, a position, and a shape of a
contour of a cut blank for said product, or of at least one glue
strip of said product.
8. The method according to claim 1, used for detecting said defects
in said folded paper products or said hygiene products during said
producing of said folded paper products or said hygiene products,
or for detecting said defects in said mailing products or said
hygiene products during said packaging of said mailing products or
said hygiene products.
9. The method according to claim 1, further for detecting defects
in printed matter that is printed onto said products by a printing
machine during said producing of said products.
10. An apparatus for producing mailing products, hygiene products,
or folded paper products, and for detecting product defects of said
products, comprising: a plurality of machine components forming
plural machine stations for performing successive steps in
producing said products; evaluation electronics; and at least one
of an imaging sensor and a capacitive sensor arranged to monitor
said products in at least one of said machine stations and
connected for signal transmission to said evaluating
electronics.
11. The apparatus according to claim 10, wherein said sensor is
arranged to monitor at least one of a size, dimensions, and a
position of a contour of at least one of a cut blank for said
products and glue strips for said products.
12. The apparatus according to claim 10, further comprising a
housing and at least one mirror, wherein said sensor is arranged in
said housing together with said at least one mirror which is
arranged to deflect an image beam path from said product to said
sensor.
13. The apparatus according to claim 10, comprising at least two of
said sensors grouped together to form a monitoring device.
Description
PRIORITY CLAIM
[0001] This application is based on and claims the priority under
35 U.S.C. .sctn.119 of German Patent Application 101 61 424.1,
filed on Dec. 13, 2001, the entire disclosure of which is
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The invention relates to a method and an apparatus for
detecting product defects in mailing products such as envelopes,
mailers, shipping bags or the like, hygiene products such as
disposable diapers, incontinence products, feminine sanitary
napkins, pads, panty liners, or the like, or folded paper products
such as paper napkins, paper towels, paper tissues, and the like,
while these products are being manufactured on a corresponding
production machine including several machine components or
stations. The invention thus generally relates to product
monitoring for product defects in the manner of an inline quality
control.
BACKGROUND INFORMATION
[0003] Modern machines for the production of the above mentioned
mailing products, hygiene products or folded paper products operate
at an extremely high speed in terms of product items per minute,
for example. As a result, it often occurs that suddenly arising
errors or defects in the products being produced are not
immediately recognized or noticed, but instead continue on through
the rest of the production and packaging process. Due to the high
production speed, this can lead to considerable product waste as
well as other considerable damages and losses. Basically, it is
essentially impossible to notice or detect defective products
during the production thereof. It is therefore important to provide
preventive or protective measures.
SUMMARY OF THE INVENTION
[0004] In view of the above, it is an object of the present
invention to provide a method and an apparatus by which product
defects of mailing products, hygiene products or folded paper
products can be reliably and quickly detected during the production
of these products, so that these defective products can be removed
from the production line or otherwise treated to prevent further
waste, loss or damage from occurring. The invention further aims to
avoid or overcome the disadvantages of the prior art, and to
achieve additional advantages, as apparent from the present
specification. The attainment of these objects is, however, not a
required limitation of the present invention.
[0005] The above objects have been achieved according to the
invention in a method and an apparatus for detecting product
defects during the production of mailing products, hygiene products
or folded paper products, wherein at least two or three
characteristic parameters or features of the product are monitored
so as to sense or detect actual values of these parameters or
features during the production of the product, and the detected
actual values are then compared with previously stored nominal
values for these characteristic parameters or features. Then,
control commands are provided to the production machine on the
basis of the testing and comparison results, so that a product that
has not been correctly produced or is otherwise defective can be
immediately ejected from the production line and/or marked so that
it may be recognized and removed from the production line by the
operating personnel, and so that the error or defect can be
corrected.
[0006] The above mentioned product monitoring is carried out with
the aid of optical and/or electrical and/or electronic means,
whereby each individual product item (i.e. each individual item of
a particular type of product) is individually monitored for
defects, with the result that the defect-free products can be
ejected or sorted out at the end of the production line.
[0007] Preferably, line cameras are utilized for carrying out the
monitoring, whereby these line cameras provide a line or
stripe-shaped image of portions of each respective product item
passing by the line camera. However, alternatively, other types of
sensors operating in different manners may be used instead of or in
addition to the line cameras, depending on the particular
application purpose.
[0008] According to a further preferred embodiment of the
invention, at least one characteristic parameter or feature of the
product is monitored with respect to the position and form thereof,
and/or several characteristic parameters or features are monitored
relative to one another with respect to the position and form
thereof, so the corresponding actual values thereof can be
permanently detected and, as in the above mentioned first case,
compared with stored nominal values for these respective
characteristic parameters or features, so that the result of the
comparison can then be used for further measures. In this context,
the nominal values of the characteristic parameters or features are
either prescribed values and/or machine-learned values or
quantities.
[0009] In this manner, it becomes possible to detect or recognize
defect locations on products directly at the time point at which
the respective defect arises, which, in many circumstances, is a
time point at which these defects have not yet had an influence on
the further production. It is also possible to eject the defective
product and to immediately correct the cause of the defect. Thus, a
secure and reliable production can be achieved in a much higher
measure than could previously be achieved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] In order that the invention may be clearly understood, it
will now be described in connection with example embodiments, with
reference to the accompanying drawings, wherein:
[0011] FIG. 1 is a schematic illustration of the apparatus
according to the invention, with reference to a production
machine;
[0012] FIG. 2 is an illustration of the apparatus according to FIG.
1 in a larger scale;
[0013] FIG. 3 is a schematic illustration of a measuring location
behind a window gluing station, whereby a line camera is arranged
as a testing or detector cell in a housing with mirrors deflecting
the beam path;
[0014] FIG. 4 is a schematic illustration of optical
image-providing sensors in a larger scale, for monitoring the glue
strips or tracks on the side flaps of a letter envelope comprising
a window;
[0015] FIG. 5 is an illustration of the image-providing sensor
above one of the glue strips, rotated by 90.degree. relative to
FIG. 4;
[0016] FIG. 6 is a schematic illustration of capacitively
functioning sensors in a multiple arrangement for monitoring the
glue strips of the closure flaps of letter envelopes that are
arranged in a staggered manner; and
[0017] FIG. 7 is an illustration of a capacitive sensor for
monitoring the glue strips on the closure flaps, rotated by
180.degree. relative to FIG. 6.
DETAILED DESCRIPTION OF A PREFERRED EXAMPLE EMBODIMENT AND OF THE
BEST MODE OF THE INVENTION
[0018] An apparatus 2 according to FIGS. 1 and 2 is provided for
monitoring the production of letter envelopes 1 and the like by
means of production machines 1'. The apparatus 2 comprises one or
more sensors in the form of line cameras 3, 3', respectively with
an associated light source 4, 4', and/or capacitively functioning
sensors 5, 5'. For example, imaging sensors are provided for
monitoring and inspecting the glue that has been provided as a
strip, line or track along the side flaps of the envelopes 1, while
capacitive sensors are predominantly provided for inspection and
monitoring of the glue provided as a strip or track along the
closure flaps of the envelopes 1.
[0019] The line cameras 3, 3' and the capacitive sensors 5, 5'
respectively provide signals to an evaluating electronics 6, e.g.
an evaluating electronic circuit 6. A rotation transmitter or
pickup 7, to which a measuring wheel can be allocated, is further
connected to the evaluating electronics 6, and basically the same
applies to a timing disk 8, to which are associated a timing cycle
initiator and a timing shaft 9 connected with the machine. The
respective output signals of the evaluating electronics 6, with the
aid of and in connection with a control electronics 10, lead to the
formation of control signals that are provided to an ejector 11,
which ejects the detected defective products 12 and moves them into
a waste or reject container 13. Instead of the ejector 11, the
control electronics 10 could alternatively activate a marking
device 14, by means of which the defective products 12' are first
marked with a visibly apparent ink or paint mark, for example, so
that these defective products 12' can later be removed from the
production line, for example manually by the machine operating
personnel.
[0020] As seen in FIG. 1, respective arrows A to F point from parts
of the apparatus 2 carrying out the product monitoring to
respective corresponding parts or areas of the production machine
1'. As is apparent from these arrows A to F and the corresponding
illustrations of FIG. 1, the electronically functioning line
cameras 3, 3' or the optical sensors on the one hand, and the
capacitively functioning sensors 5, 5' on the other hand, are
allocated to and respectively arranged at defined locations or
exactly defined stations of the production machine 1'.
[0021] Station 15 (arrow A) is a printing station, in which a
certain predefined text, picture, or other printed material is
printed onto the original starting material 16, which is initially
still in a continuous web shape. In this station, the exact
position of the text or picture or other printed material is
determined by the respective sensor or sensors.
[0022] In the following or subsequent station 17 (arrow B), the
window material 19 (FIG. 1 or 3) is arranged and e.g. glued onto
the window cut-out opening for the window 18 of a partially
fabricated letter envelope 1 or a corresponding intermediate
product 20, for an envelope 1 that is ultimately to have a window
18. In this station 17, at least one line camera 3 monitors the
size and position of the window material 19 relative to the opening
for the window 18.
[0023] In a further station 21 (arrow C) of the production machine
1', glue strips or tracks 22 have been provided on the side flaps
23 of a partially fabricated letter envelope 1, and respective
imaging sensors carry out a monitoring or sensor detection of the
presence, proper size, and proper position of the respective glue
strips 22 on the side flaps 23, as this is also shown in FIGS. 4
and 5.
[0024] Next, in the area of the final closure flap folding station
26 (arrow D), or at the inlet of a drying path, the invention
carries out a monitoring or sensing of the respective glue strips
or tracks 24 that have been provided on the closure flaps 25 of the
letter envelopes 1. In this context, the substantially completed
letter envelopes 1 run through the closure flap folding station 26
in a staggered position or arrangement, as can be seen in FIGS. 1
and 6.
[0025] The ejection of the detected defective products 12 (arrow E)
by means of the ejector 11 is carried out in the area of a stacking
station 27, and/or, the marking of defective products 12' (arrow F)
is carried out in the area of a stacking area or stacking range 28
of the stacking station 27, or before or upstream of the ejector
11.
[0026] Alternatively, the marking of defective products 12'
according to arrow F can be achieved in a variable manner farther
toward the front in the production path or production line, so that
especially the marking can be carried out before the defective
product 12' arrives at the ejector 11.
[0027] It should further be understood, that the line cameras 3, 3'
can also be used for detecting the outer contour 29 (as shown in
FIG. 4) of the individual cut envelope blanks 30 according to FIG.
2, or for detecting the respective corresponding forms or shapes in
the case of web-shaped intermediate products 20 according to FIG.
1. Also, the text printed onto letter envelopes and shipping bags,
and especially the inside printing, can be monitored by means of
respective appropriately arranged line cameras. The same
considerations essentially also apply for using such line cameras
for monitoring pre-fold, score or crease lines in the lengthwise
direction or the crosswise direction of the envelope being
fabricated, or for all other characteristic features and parameters
of the respective products.
[0028] There may be machine components located in the individual
stations of the production machine, which make it difficult to
monitor the respective characteristic parameter of interest using
sensors. For example, in the area of the station 31 serving to glue
the window material 19 onto the window cut-out of the envelope,
various machine components may be arranged "in the way" of a direct
arrangement of monitoring sensors, so that an interfering contour
32 must be taken into consideration. Such an interfering contour 32
of a machine component or the like is merely schematically
indicated as a contour line 33 in FIG. 3. This interfering contour
32 makes it necessary to arrange the line camera 3 serving as a
sensor at a sloping angle relative to the product being monitored,
i.e. concretely relative to the partially fabricated letter
envelope 1, because the interfering contour 32 of the machine
component makes it impossible to arrange the line camera 3 in an
orientation perpendicular to the partially fabricated letter
envelope 1.
[0029] As shown in the illustration in FIG. 3, the optical sensor
or the line camera 3 is arranged offset relative to the product to
be monitored, and oriented with its image receiving optics 34
facing away from the product to be monitored. Furthermore, plural
mirrors 35, and particularly in the present example embodiment five
mirrors 35, are arranged appropriately to deflect the beam path 36
of the image of the product, so that this beam path 36 first
extends perpendicularly from the product, and is then multiply
deflected to finally enter in an axis-parallel manner into the
receiving optics 34 of the line camera 3. Both the line camera 3
and the mirrors 35 are suitably arranged in a housing 37, of which
the outer contour is fitted or adapted to the space still remaining
in consideration of the interfering contour 32 of the station 31.
In the embodiment concretely illustrated in FIG. 3, this results in
the fact that the beam path 36 includes a beam path portion or leg
38 which at first extends nearly parallel to the axis 39 of the
optics 34 of the line camera 3. The image received by the first
mirror 35 is thus deflected at angles multiple times before it can
be evaluated.
[0030] In the example embodiment concretely illustrated in FIG. 3,
the housing 37 comprises a first housing part 40 arranged
immediately adjacent to the product, a second housing part 41 that
adjoins and extends at an angle from the first housing part 40 and
receives the line camera, and a third housing part 42 in which the
respective mirrors 35 are arranged, which deflect the beam path 36
back into the optics 34 of the line camera 3.
[0031] The components illustrated in FIG. 3 form a monitoring
arrangement 43 with an image deflection. This monitoring
arrangement 43 concretely serves for monitoring the proper
defect-free fabrication of the window 18 of the resultant product
such as the letter envelope 1.
[0032] Similarly, the monitoring of the glue strips 22 on the side
flaps 23 of the still not-yet-finished letter envelope 1 is carried
out according to FIG. 4 with imaging sensors 5, past which the
envelope 1 is conveyed. Each imaging sensor 5 includes a line
camera 3 and a light source 4, respectively, as this is shown in
FIG. 5.
[0033] A respective imaging sensor 5 is provided for each glue
strip 22. Suitably, the line camera 3 and the light source 4 are
arranged one after another in the motion direction of the almost
completed letter envelope 1, as this is shown in FIG. 5. However,
other variants in this regard are basically also suitable depending
on the particular application.
[0034] The monitoring of the glue strips 24 on the closure flaps 25
is suitably carried out using plural capacitively functioning
sensors 5', which together or in common respectively sense one or
more glue strips 24. Respectively one capacitive sensor 5' is
arranged over each one of the two ends of the glue strips 24, while
a third capacitive sensor 5' is located approximately at the middle
above the respective glue strip or glue strips 24. Together, these
capacitive sensors 5' form a monitoring device or arrangement
43.
[0035] The capacitive sensor or sensors 5' respectively each
comprise a measuring electrode 46 and a shielding electrode 47. A
component of the production machine 1' itself serves as the counter
electrode.
[0036] Through the aid of the inventive features of the various
example embodiments described herein, it is possible to permanently
detect or sense and measure actual existing values of one or more
characteristic parameters or features of the product with respect
to its length or dimensions and/or form or shape, or with respect
to the position and/or form relative to each other, in a permanent
manner, and to compare these detected actual values with stored
nominal values respectively associated with these characteristic
parameters or features of the product (for example stored nominal
values defining the proper size, shape and position of the window
opening, the window film material, the glue strips, the folded
flaps, the printed text, etc. of the envelope being produced).
[0037] Then, the result of this comparison (e.g. the actual value
is equal to the nominal value, or the actual value is within an
acceptable tolerance range around the nominal value, or the actual
value is unacceptably greater than the nominal value, or the actual
value is unacceptably less than the nominal value) is used for
controlling further measures. For example, the result of the
comparison can be indicated on a control panel or the like for
informing the machine operating personnel, and/or the result can be
used to initiate corrective measures and/or for marking the
respective detected defective product, and/or for ejecting the
respective detected defective product out of the production line or
production machine, and/or the result can be permanently documented
for later review and analysis.
[0038] The invention is not limited to the concrete measures that
have been described and illustrated in connection with the drawing
figures herein, and especially is not limited to the monitoring of
the glue strips and windows. For example, other characteristic
parameters or features of the product, for example such as the rim
or edge of the window cut-out opening in the cut envelope blank, as
well as other cut lines of the blank, may be advantageously
monitored according to the invention.
[0039] Also, the invention is not limited to use in connection with
production machines for producing letter envelopes, shipping bags,
and other such mailing products, as described in the detailed
embodiments herein. To the contrary, the inventive method and
apparatus can also be used in machines and/or stations and/or
methods for stamp-cutting of envelope blanks and shipping bag
blanks, or in machines for forming, folding or producing
inter-folded towels or the like, folded paper tissues or folded
paper napkins or the like, of which various characteristic
parameters can be detected by imaging and/or capacitive
sensors.
[0040] Basically the same point also pertains to machines and
processes for producing hygiene products, for example such as
feminine sanitary napkins, pads, panty liners, disposable diapers,
incontinence products, and the like. Not only production machines
for producing the above described products, but also packaging
machines for packaging the above described products can be
monitored using the inventive method and sensor arrangement, so
that it immediately becomes recognizable, if a product has not been
properly packaged.
[0041] Furthermore, various types of sensors can be used according
to the invention for monitoring the results of printed text or
images or the like produced by printing machines that are used in
connection with the above mentioned machines.
[0042] Although the invention has been described with reference to
specific example embodiments, it will be appreciated that it is
intended to cover all modifications and equivalents within the
scope of the appended claims. It should also be understood that the
present disclosure includes all possible combinations of any
individual features recited in any of the appended claims.
* * * * *