Abstract:
A method includes receiving a first image of a first line of perforations in a sheet product, processing the first image to determine whether the first line of perforations are within specifications, and outputting an indication to an operator indicative that the first line of perforations are not within specifications responsive to determining that the first line of perforations are not within specifications.

Description:
CLAIM FOR PRIORITY 
     This non-provisional application is based upon U.S. Provisional Application No. 61/560,458, filed Nov. 16, 2011. The priority of U.S. Provisional Application No. 61/560,458 is hereby claimed and the disclosure thereof is incorporated in its entirety into this non-provisional application by reference thereto. 
    
    
     BACKGROUND OF THE INVENTION 
     The subject matter disclosed herein relates to methods and systems for fabricating sheet products, and particularly to forming rolls of sheet products. 
     Many sheet products are fabricated into rolls of sheet products. The sheet products may include lines of perforations that are formed by passing the sheet product through a perforation apparatus that cuts perforations in the sheet product. Once the perforations are formed, the sheet product may be wound into a roll of sheet products. The perforations allow a user to easily separate portions of the sheet product from a roll. 
     BRIEF DESCRIPTION OF THE INVENTION 
     According to one aspect of the invention, a method includes receiving a first image of a first line of perforations in a sheet product, processing the first image to determine whether the first line of perforations are within specifications, and outputting an indication to an operator indicative that the first line of perforations are not within specifications responsive to determining that the first line of perforations are not within specifications. 
     According to another aspect of the invention, a system includes a first camera, and a processor operative to receive a first image of a first line of perforations formed by a perforating arrangement in a sheet product from the first camera, process first image to determine whether the first line of perforations are within specifications, output an indication to an operator indicative that the first line of perforations are not within specifications responsive to determining that the first line of perforations are not within specifications. 
     These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG. 1  illustrates an exemplary portion of a system for fabricating perforations in a sheet product and rolling the sheet product. 
         FIG. 2  illustrates a side view of a portion of the system. 
         FIG. 3  illustrates a detailed view of the region  3  of  FIG. 2 . 
         FIG. 4  illustrates a block diagram of the system. 
         FIGS. 5-7  illustrate examples of images of lines of perforation in the sheet product. 
         FIGS. 8A and 8B  illustrate a block diagram of an exemplary method that may be performed by the system of  FIG. 1 . 
         FIG. 9  illustrates a block diagram of an alternate exemplary method that may be performed by the system of  FIG. 1 . 
     
    
    
     The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Sheet products are often fabricated into rolls of sheet products. Prior to forming the rolls, the sheet product may be processed to fabricate lines of perforations that are usually arranged parallel to the rotational axis of the rolls. The lines of perforations allow a user to easily separate portions of the sheet material from the roll. The lines of perforations are often formed by passing the sheet product through a perforating mechanism that forms the perforations. The distance or interference between the anvil and knife affects quality of the cut. In operation, an operator typically inspects the line of perforations to determine if the line of perforations is within desired specifications. The operator may then adjust the perforating mechanism if desired to form the proper perforations. Once the perforations have been formed, the sheet product could be wound to form a roll having a desired length. 
     The term “sheet products” as used herein is inclusive of natural and/or synthetic cloth or paper sheets. Sheet products may include both woven and non-woven articles. There are a wide variety of nonwoven processes and they can be either wetlaid or drylaid. Some examples include hydroentangled (sometimes called spunlace), DRC (double re-creped), airlaid, spunbond, carded, paper towel, and meltblown sheet products. Further, sheet products may contain fibrous cellulosic materials that may be derived from natural sources, such as wood pulp fibers, as well as other fibrous material characterized by having hydroxyl groups attached to the polymer backbone. These include glass fibers and synthetic fibers modified with hydroxyl groups. Examples of sheet products include, but are not limited to, wipers, napkins, tissues, towels or other fibrous, film, polymer, or filamentary products. 
     In general sheet products are thin in comparison to their length and width and exhibit a relatively flat planar configuration and are flexible to permit folding, rolling, stacking, and the like. The sheet product may have perforations extending in lines across its width to separate individual sheets and facilitate separation or tearing of individual sheets from a roll or folded arrangement at discrete intervals. Individual sheets may be sized as desired to accommodate the many uses of the sheet products. For example, a row of perforations may be formed every 13 inches (33 cm), or other defined interval, to define a universally sized sheet. 
       FIG. 1  illustrates an exemplary portion of a system  100  for fabricating perforations in a sheet product and rolling the sheet product. Alternate embodiments may include similar systems that may be, for example, orientated horizontally or vertically, but operate in a similar manner. 
     In this regard, the system  100  includes a perforating arrangement  102  that includes an anvil roller  104  and a perforations roller  106 . The perforations roller  106  includes a perforating member that is operative to form a line of perforations  105  in the sheet product  101  as the sheet product  101  passes between the perforations roller  106  and the anvil roller  104 . Once the perforations  105  are formed in the sheet product  101 , the sheet product  101  is wound into a roll  103 . The quality of the cut is determined by the position of the perforations roller  106  relative to the anvil roller  104 . The sheet product  101  passes through an interference defined by the perforations roller  106  and the anvil roller  104 . The interference may be adjusted with a roller position adjustment mechanism  112  such that a smaller distance between the perforations roller  106  and the anvil roller  104  results in greater interference between the perforations roller  106  and the anvil roller  104 , while a larger distance between the perforations roller  106  and the anvil roller  104  results in less interference between the perforations roller  106  and the anvil roller  104 . When properly adjusted, the interference between the perforations roller  106  and the anvil roller  104  exerts a proper amount of pressure to sever the fibers in the sheet product  101  resulting in perforations  105  having desired dimensions. The adjustment mechanism  112  may include, for example, motors or servos mechanically linked to the perforating arrangement  102  to adjust the position of the anvil roller  104  relative to the perforations roller  106 . In the illustrated embodiment, the system  100  includes an arrangement of one or more visual devices  108 , such as, for example, cameras or other similar devices, that may be used to visually determine whether the desired perforations  105  have been formed in the sheet product  101 . The system  100  may then properly adjust the position of the perforations roller  106  relative to the anvil roller  104  to control the quality of the cut. 
     The system  100  may include one or more backlights  110  that are arranged in opposition to the visual device  108  such that the sheet product  101  passes between the visual device  108  and the backlights  110 . The backlights  110  are operative to illuminate the line of perforations  105  by passing light through the perforations  105 , which improves the images output by the visual device  108 . 
       FIG. 2  illustrates a side view of a portion of the system  100  that includes the perforating arrangement  102 , the visual devices  108 , backlights  110 , and a roll  103  that is formed following the formation of the perforations  105  ( FIG. 1 ) in the sheet product  101  using a suitable roll forming apparatus. In the illustrated embodiment, the system  100  may include a second visual device(s)  114  that may be used to determine a diameter (d) of the roll  103 . For example, the second visual device  114  may be used to determine whether the roll  103  is within a desired diameter specification. If not, the system  100  will signal an output to downstream equipment to automatically or manually remove the roll  103  from production if desired. 
       FIG. 3  illustrates a detailed view of the region  3  of  FIG. 2 . In this regard, perforations roller  106  includes a knife portion  304 . The anvil roller  104  includes an anvil portion  302 . The anvil roller  104  and the perforations roller  106  of the perforating arrangement  102  define an interference having a width G. The width of the interference affects the amount of interference between the perforations roller  106  and the anvil roller  104 . 
       FIG. 4  illustrates a block diagram of the system  100 . Referring to  FIG. 4  with periodic reference to  FIG. 1 , the system  100  includes a processor  402  that is communicatively connected to a display device  404 , a memory device  408 , and input devices  406 . The visual device  108  output images of the lines of perforations  105  in the sheet product  101  as the sheet product  101  exits the perforating arrangement  102 . The images from the visual device  108  are received by the processor  402 . The processor  402  may use a stored image of a line of perforations  105  that has a desired shape and profile, and adjust the relative position of the rollers  104  and  106  in the perforating arrangement  102  using a roller position adjustment mechanism  112  so that subsequent perforations  105  substantially match the desired shape and profile of the perforations  105  depicted in the stored image. The adjustment mechanism  112  may include, for example, one or more motors that may be controlled by the processor  402  to adjust an interference between the anvil roller  104  and the perforations roller  106 . The processor  402  may use logic that determines whether the lines of perforations  105  are, for example, cut with too large of an interference. If the perforations  105  are cut with too large of an interference, the processor  402  may reduce the interference G (of  FIG. 3 ) using the adjustment mechanism  112 . Alternatively, if the lines of perforations  105  are cut with too small of an interference, the processor  402  may use the adjustment mechanism  112  to increase the interference G. 
       FIGS. 5-7  illustrate examples of base images  500 ,  600 , and  700  of lines of perforation in the sheet product  101  ( FIG. 1 ). The base images  500 ,  600 , and  700  represent examples of processed images that may be used by the processor  402  (of  FIG. 4 ) to determine whether the lines of perforations  105  are within desired specifications. In this regard  FIG. 5 ,  FIG. 6 , and  FIG. 7  illustrate exemplary base images  500 ,  600 , and  700  of lines of perforations of a portion of the sheet product  101 . The perforations are shown as shaded regions  503 ,  603 , and  703 . For illustrative purposes,  FIG. 5 ,  FIG. 6 , and  FIG. 7  illustrate lines of perforations that are within specifications. For example, the width (W), length (L), and spacing (S) distances and shapes of the shaded regions  503 ,  603 , and  703  may be measured to determine whether the lines of perforations (partially defined by the shaded regions  503 ,  603 , and  703 ) are within specifications. The base images  500 ,  600 , and  700  (or a similar image) may be used as the base image described above. If the width (W), length (L), and spacing (S) distances and shapes of the shaded regions  503 ,  603 , and  703  vary from the base image used by the processor  402 , this indicates that the perforations have been cut with a wrong interference G. As discussed above, the processor  402  may use a comparison of the base image (e.g., images  500 ,  600 , and  700 ) with the size and shape of the perforations in received images to determine whether the length, width, and spacing of the perforations in the received images are close (i.e., within specifications or thresholds) to the base image. 
       FIGS. 8A and 8B  illustrate a block diagram of an exemplary method that may be performed by the system  100  ( FIG. 1 ) described above. In this regard, in block  802 , the processor  402  (of  FIG. 4 ) receives an image of a line of perforations  105  (of  FIG. 1 ). In block  804 , the processor  402  processes the image. The image may be processed to for example, account for variations in the positions of the perforations  105  relative to the frame of the image. The processing may include, for example, other visual processing methods such as processing a video image to identify a frame of the video image that includes a line of perforations  105 . The frame of the video image may be used as the received image. The processing may also include, inverting the grayscale or color scale of the pixels of the image, or other suitable imaging processing methods. In block  806 , the processor  402  compares the received image with a base image that may be stored in the memory device  408  (of  FIG. 4 ). The base image includes an image of a line of perforations  105  having a desired depth, shape, and profile. The processor  402  determines whether the perforations  105  in the received image are within a threshold or specification range (i.e., whether the received image is sufficiently similar to the base image) in block  808 . If the perforations  105  are not within specifications, the processor  402  increments a counter (that may be stored on the processor  402 ) in block  810 . If the perforations  105  are within specifications, the processor  402  resets the counter (i.e., sets the counter to zero (0) in block  811 . In block  812 , the processor  402  determines whether the counter has reached a threshold count and outputs an indication that the counter has reached the threshold count in block  814 . The indication may be output via the display device  404  ( FIG. 4 ) that may include, for example, a display screen or other type of visual indicator device such as an indicator light, or in some embodiments an audible indication may be output to an operator. The fabrication process may be automatically or manually stopped or delayed in block  814  allowing an operator to remove the sheet product  101  with the out of specification perforations  105  from processing or to identify and correct the problem causing the out of specification perforations  105 . If the counter has not reached the threshold, the processor  402  determines whether the perforations  105  indicate that the cutters are set too deep or too shallow in block  816 . If the perforations  105  are too deep, the processor  402  adjusts the interference G (of  FIG. 3 ) to increase the width of the interference G in block  818 . If the perforations  105  are too shallow, in block  820 , the processor  402  decreases the width of the interference G. In block  822  (of  FIG. 8B ), the processor  402  receives and processes an image of the roll  103  (of  FIG. 2 ) from the second visual device  114 . The processor  402  may identify the tangential edges of the roll  103  and calculate the diameter of the roll  103  in block  824 . In block  826 , the processor  402  determines whether the measured diameter is within a specification threshold for the diameter of the roll  103 . If the measured diameter is not within the specification threshold, an indication may be output in block  828 . If desired, the fabrication process may be stopped or delayed to allow the roll  103  to be removed from further fabrication. In block  830 , an indication that the diameter of the roll  103  is within specifications may be output to an operator. 
     In an alternate exemplary embodiment, the system  100  (of  FIG. 1 ) may operate in an alternate exemplary method similar to the method described above in  FIG. 8A . Referring to  FIG. 9 , in block  814  an indication is output to an operator that the perforations  105  are out of specifications. The indication may include, for example, a visual indicator on the display device  404  (of  FIG. 4 ), a visual indicator such as, for example a light, and/or an audible indicator. The operator may stop the fabrication process manually, or the system  100  may be set to stop the fabrication process upon determining that the counter has reached the threshold (in block  812 ). In block  916 , the operator may troubleshoot to identify the cause of the out of specification perforations  105  and may correct the problem. Once the problem is corrected, the counter may be set to zero in block  811  and the fabrication process may begin again in block  802 . 
     While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.