Patent Application
20070081715
The present application relates to a quality control system and method for inspecting moving pre-printed web material.
Many products are supplied in sealed bags, pouches or other packages formed from thin films or other flexible materials. For example, foodstuffs, tobacco products, small parts or loose items such as pharmaceuticals or other medical accessories are commonly provided in pouches or bags formed from flexible film material.
The production of these products is carried out by forming such products as elongated webs which are thereafter segmented by cutting to yield lengths which are usable by the customer. While the character of the material along the length of the web may appear to be uniform, in many instances there are variations along the length of such webs. These variations may arise for example in the form of instantaneous or running defects within the material forming the web.
Methods of inspecting web material following production have been developed to identify the location and nature of variations along the length of the web material. A continuous, non-stop inspection method is needed to reduce process downtime.
In an aspect, a method for inspecting moving web material on a label application unit is provided. The web material includes repeated, pre-printed sections wherein each section corresponds to an individual package unit. The method includes detecting a position indicator located on the web material using a sensor where multiple sections of the moving web material includes a position indicator. A die section is moved in response to detection of the position indicator to re-position the die section for a cutting operation. It is determined whether movement of the die section is beyond a predetermined range using a processor. One or more of the method steps are performed for more than one pre-printed section of the moving web material.
In another aspect, a system for inspecting moving web material on a label application unit includes a first scanner arranged and configured to sense a position indicator carried by the moving web material. A second scanner is arranged and configured to sense a pre-printed mark. A sensor is arranged and configured to sense an edge of the moving web material. A detector is arranged and configured to detect an increase in web thickness as the moving web material passes thereby. A controller receives signals from at least one of the first scanner, second scanner, sensor and detector.
Other advantages and features of the invention will be apparent from the following description of particular embodiments and from the claims.
Referring to
Label application apparatus 10 includes an unwind unit 16 (e.g., commercially available from Kenne Technology, Inc. (KTI), Beloit, Ill.) where rolls 18 and 20 of pre-printed web material are continuously spliced in register (e.g., tolerance of +/−0.125 inch) followed by an edge reading ultrasonic web guide 22 (e.g., commercially available from AccuWeb, Inc., Madison, Wis.). After passing through a nipped infeed tensioning dancer 24, the web material 12 wraps around two 12 inch drums 26 and 28, where at one of either of the two 12 inch drums, a label head 30, 32 (e.g., commercially available from Quadrel Labeling Systems, Inc., Mentor, Ohio) using a printed eye mark (described below) will apply a label. The two label heads 30, 32 operate in tandem to provide a non-stop application. However, only one label head or more than two label heads may be used.
After the label application, the web material 12 is die cut in register to the printed eye mark from the underside at a die cut station 34. The web material 12 passes through a quality assurance section 36, described below, a flagging label head 38, an exit nipped pacing roll 40 and a turret rewind 42. Finished product rolls 44, 46, 48 are spliced in register on a turret rewinder (e.g., commercially available from KTI), at a designated footage.
Referring now to
A. Die Register In Web Running Direction
Referring to
In operation, die section 64 (e.g., servo controlled die 66 and anvil 68; see FIG. 1) of die cut station 34 is verified to be held to a predetermined tolerance (e.g., +/−0.1875 inch) from a standard. An optical contrast scanner 70 (or die register sensor) reads one of the eye marks 62 in order to determine position of the web material 12. The determined position is compared to a theoretical expectancy of the eye mark 62 that is related to the number of teeth (e.g., 160 teeth, ⅛ inch CP) of the die 66. Depending on this comparison, the die section 64 may or may not be moved in the web running direction shown by arrow 65. In one embodiment, the correction of the die section 64 is limited to a maximum tolerance (e.g., +/−0.1875 inch). Any correction of the die section 64 greater than the maximum tolerance will be marked as “out of process window” and a signal may be sent, for example, to a programmable logic controller (e.g., commercially available from Allen Bradley).
B. Label Placement In Web Running Direction
Referring also to
Optical contrast scanners 92 and 94 are offset from each other in the web running direction (e.g., 0.375 inch) to create a label sensor gate. A luminescence scanner 96 (e.g., such as a QL55 microprocessor-controlled luminescence sensor, commercially available from Banner Engineering Corp.) is located in the web running direction between the scanners 92 and 94 to detect the leading edge varnish block 76.
In operation, optical contrast scanner 92 detects one of the eye marks 62 as the eye mark 62 passes thereunder, which opens the gate. The luminescence scanner 96 then reads the leading edge varnish block 76 in order to determine the position of the label. Then, the optical contrast scanner 94 reads the second eye mark 62, which closes the gate. The information is fed to the PLC and is processed to track each repeat section of the web material 12. If the gate closes before the luminescence scanner reads the leading edge of the varnish block, then the tolerance will be marked “out of process window” or the label is missing and a corresponding signal is sent to the PLC.
C. Die Cut Across Web Running Direction
Referring to
In some embodiments, an imager, such as camera 106 (e.g., commercially available from Handy Scan) may be used to inspect the quality assurance functions at various repeat sections of web material 12. In some embodiments, this inspection may not be continuous. For example, the web material 12 may be moving in the web running direction at approximately 250 feet per minute and every other section of web material monitored with the camera 106. In one embodiment, the camera 106 takes still pictures every other repeat section and those pictures are monitored by an operator of the apparatus 10.
D. Label Placement Across Web Running Direction
Referring briefly to
E. Wrinkle Detection
A wrinkle detection assembly 112 is used to detect regions of increased web material thickness. Referring to
In some embodiments, the PLC program runs a cascade ladder, which tracks each repeat of the web material 12 through the quality control method 50 to the flagging or defect label, label head 38 (
It is to be clearly understood that the above description is intended by way of illustration and example only and is not intended to be taken by way of limitation, and that changes and modifications are possible. Accordingly, other embodiments are contemplated and modifications and changes could be made without departing from the scope of this application as expressed by any claims now included or hereafter added.
The present application claims priority to provisional U.S. application Ser. No. 60/724,146, filed Oct. 6, 2005, the content of which is hereby incorporated by reference as if fully set forth herein.
| Number | Date | Country | |
|---|---|---|---|
| 60724146 | Oct 2005 | US |
