Abstract:
A plastic bag is supplied as a continuously attached length of plural bags, each bag being separated from adjacent bags along a supply length by a perforated tear line. A seal which runs codirectionally with the tear line forms a closed bottom for each bag, such that when a bag is separated along the tear line from a remainder of the supply, the bag is enclosed along three of its four edges enabling containment of produce or other items placed therein via the opening at the fourth, and remaining edge of the bag which is coextensive with the perforation line. The supply length of bags is advantageously stored on a roll, fan folded, bundled or compactly stored in other suitable manner permitting advancement of consecutive bags when pulled out of the stored condition by a user. The perforation tear line cuts entirely through the continuous web supply of bags, however, the perforation along one side the bag is broken, such that the bag presents an open flap through which contents can be added to each bag prior to its removal fro the remainder of the continuous bag supply. A method of using the bags for packaging of produce, groceries or other articles generally selected at point of sale and which are generally segregated by type for later pricing by weight or unit, permits a user to at least partially fill a bag prior to removal from a continuous supply of plural bags.

Description:
This is a continuation-in-part of copending application Ser. No. 10/170,522 filed on Jun. 13, 2002, now abandoned, which is incorporated herein by reference. 

   BACKGROUND 
   The present invention relates to a web of pre-opened bags in a compact dispensing format and a method for packaging point-of-purchase items using such pre-opened bags. 
   Plastic bags stored in bulk, for example, on supply rolls containing a plurality of attached bags, have conventionally been provided in supermarkets and other locations to provide the consumer with a convenient means for packaging items, such as, for example, articles of produce and other groceries, selected for purchase. Since, typically, fruits and vegetables are uniquely priced per unit of weight, packaging each type of produce in its own separate bag permits simplified determination of price at checkout, while concomitantly protecting the contents from contamination, damage and moisture loss. The lightweight nature of the bags obviates the need for taking a tare weight of the bag prior to weighing of the merchandise, further adding to the convenience attendant their use. 
   Heretofore, such bags have typically been provided on webs contained on continuous supply rolls having tear lines between adjacent bags to readily permit separation of individual bags from the remainder of a supply roll. Once removed, a bag is typically opened at the tear line and contents may then be inserted therein. Since attached bags are initially separated at a tear line while on a supply roll, the bags must normally be removed from the roll in order to permit filling with produce or other items. This can prove to be inconvenient, especially if a person&#39;s hands are full. It is also often difficult to open such bags since, as a result of a manufacturing process, a bag opening can cling together, sometimes as the result of static electricity. Frequently such bags can be difficult to open when a user&#39;s hands are cold or excessively dry. It can also be difficult for a user to perceive the location or the correct end of a bag at which the opening is positioned. 
   In some applications, a supply roll containing a web of bags is part of a larger storage form that allows the supply roll to rotate freely as each bag is being dispensed. However, such permitted free rotation of the supply roll can further complicate the dispensing of bags, especially if the user&#39;s hands are full, cold or dry, or if there is static cling or other inherent difficulties encountered while attempting to detach and/or to open a bag from the web. Frequently, such encountered difficulties can cause the accidental dispensing of multiple bags from the freely rotating supply roll. This can significantly increase retailer costs and detract from the general tidiness and appearance of the area immediately surrounding the storage form due to sloppy supply roll unfurling and the local accumulation of unwanted dispensed or partially dispensed bags. Free rotation of the supply roll could also complicate the opening of a bag prior to removal from the web. 
   It would therefore be highly desirable to provide a bag that is supplied from a continuously attached web of bags that would permit a user to easily open and fill each bag as it is being dispensed from a supply roll without requiring each bag to be first removed from the continuous web. Furthermore, a method of packaging using such pre-opened bags would also provide an advantage over conventionally practiced point-of-purchase packaging methods by virtue of the fact that the additional user step of opening each bag prior to filling would be eliminated. In addition, configuring a storage form to restrict free rotation of a supply roll and to increase bag tension would further enhance the dispensing and usefulness of such pre-opened bags. 
   SUMMARY 
   A web of pre-opened bags is supplied in a continuously attached supply length in which each pre-opened bag is separated from an adjacent bag by a tear line. A seal, which runs co-directionally with the tear line, forms a closing near the bottom of each pre-opened bag such that when a bag is separated along the tear line from a remainder of the supply length, the bag is enclosed along three of its four edges, enabling containment of produce or other items placed therein via the opening at the fourth and remaining insertion edge of the bag which is coextensive with the tear line. The supply length of bags is advantageously stored on a roll or is fan folded, bundlized, or compactly stored in another suitable web manner to permit advancement of consecutive bags when pulled from the stored web condition by a user. Each tear line extends entirely across the continuous web supply of bags. However, the tear line along one side or ply of each bag is broken to form an insertion edge such that each bag, while the other side of each bag is still attached to the web, presents an open end through which contents can be added to prior to the dispensing of the bag. The side of each pre-opened bag that is broken along the tear line defines an open ply and the side of each bag that remains attached along the tear line defines an attached ply. 
   In one embodiment, an insertion edge of the open ply is at least partially separated from at least one of the open ply and the attached ply of the bag adjacent it on the tear line and the open ply is capable of extending to a position substantially flush with the tear line between them. However, at least one of the insertion edge of the open ply of the bag and the open ply of the second bag are at least partially folded back from the tear line making it easier for a purchaser to grip the insertion edge. 
   Briefly stated, a method of using the above described pre-opened bags for packaging of produce, groceries or other articles generally selected at point-of-purchase, and which are generally segregated by type for later pricing by weight or unit, permits a user to at least partially fill a bag prior to removal from a web of bags. 
   Although not intended to be limiting to the invention as broadly contemplated, pre-opened bags produced in accordance with the invention can typically present dimensions between about 10″w×14″h and about 12″w×20″h. Some embodiments of the invention may include pre-opened bags as large as 16″w×24″h or larger. Such dimensions are deemed to provide a suitable accommodating volume to meet the needs of a consumer encountered in connection with the above range of uses. In addition, although similarly not intended to be limiting to practice of the disclosed method in accordance with the invention, a wall thickness of the bags of less than about 1.50 mils (thousandths of an inch) can, for some applications, be deemed advantageous to practice of the invention. In some typical applications, a wall thickness of the bags produced in accordance with the invention lies in a range of about 0.3 mils to about 0.9 mils. 
   Some specific embodiments of the invention also include a storage form that is capable of producing tension as pre-opened bags from a web are pulled, the additional tension allowing for at least the partial drawing apart of plies during the dispensing of the pre-opened bags. 
   The above, and other objects, features and advantages of the present invention will become apparent from the following description read in conjunction with the accompanying drawings. Those skilled in the art will realize that this invention is capable of embodiments that are different from those shown and that details of the invention can be changed in various manners without departing from the scope of this invention. Accordingly, the drawings and descriptions are to be regarded as including such equivalent webs of bags and packaging methods that do not depart from the spirit and scope of this invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a web of continuously attached pre-opened bags on a supply roll in accordance with an embodiment of the invention shown partially unrolled; 
       FIG. 2  is a schematic view of a production line for producing a web comprising a length of continuously attached bags in accordance with an embodiment of the invention; 
       FIG. 3  is a schematic view of a rewinding station for providing a desired orientation of an opening of the bags relative to the continuous supply when dispensed therefrom; 
       FIG. 4A  depicts a web of continuously attached pre-opened bags according to one embodiment of the invention; 
       FIG. 4B  depicts the web of continuously attached pre-opened bags of  FIG. 4A  having a partially folded insertion edge; 
       FIG. 4C  depicts the web of continuously attached pre-opened bags of  FIG. 4A  having a partially folded insertion edge; 
       FIG. 5A  depicts a web of continuously attached pre-opened bags according to one embodiment of the invention; 
       FIG. 5B  depicts the web of continuously attached pre-opened bags of  FIG. 5A  having partially folded excess portions; 
       FIG. 5C  depicts the web of continuously attached pre-opened bags of  FIG. 5A  having partially folded excess portions and a partially folded insertion edge; 
       FIG. 5D  depicts the web of continuously attached pre-opened bags of  FIG. 5A  having a partially folded excess portion and a partially folded insertion edge; 
       FIG. 6  depicts a web of continuously attached pre-opened bags according to one embodiment of the invention; 
       FIG. 7  depicts a web of continuously attached pre-opened bags according to one embodiment of the invention; 
       FIG. 8  depicts a web of continuously attached pre-opened bags according to one embodiment of the invention; 
       FIG. 9A  depicts a web of continuously attached pre-opened bags according to one embodiment of the invention prior to being grasped and pulled by a user; 
       FIG. 9B  depicts the web of continuously attached pre-opened bags of  FIG. 9A  being grasped and pulled by a user; 
       FIG. 10  is a perspective view of the web of continuously attached pre-opened bags of  FIG. 1  after being rewound on a supply roll; 
       FIG. 11A  depicts a web of continuously attached pre-opened bags contained on a storage form according to one embodiment of the invention; 
       FIG. 11B  depicts a web of continuously attached pre-opened bags contained on a storage form according to one embodiment of the invention; 
       FIG. 12  depicts a web of continuously attached pre-opened bags contained on a storage form according to one embodiment of the invention; 
       FIG. 13A  is an exploded perspective view of a web of continuously attached pre-opened bags contained on a storage form according to one embodiment of the invention; and 
       FIG. 13B  is a side view of the web of continuously attached pre-opened bags contained on a storage form depicted in FIG.  13 A. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to the drawings, similar reference numerals are used to designate the same or corresponding parts throughout the several embodiments and figures. In some drawings, some specific embodiment variations in corresponding parts are denoted with the addition of lower case letters to reference numerals. 
   In  FIG. 1 , a web of continuously attached plastic pre-opened bags is depicted generally at  10   a . The web  10   a  supplies a continuous bulk supply of individual pre-opened bags  10   a ′, that are provided on a supply roll  1   a . As part of the web  10   a , each pre-opened bag  10   a ′ is separated from an adjacent bag  10   a ′ by a perforated tear line  2   a  extending through the web of bags  10   a  crosswise to a supply length of the continuous web  10   a . Although the tear line  2   a  is shown and described in  FIG. 1  as being perforated, it will be appreciated that other appropriate methods of allowing for the easy detachment of adjacent bags  10   a , such as but not limited to linearly reducing bag thickness, razor slitting, fold weakening, and the like are also contemplated to be within the intended invention scope. 
   Each bag  10   a ′ is also sealed at a seal end  19   a  adjacent the tear lines  2   a  along a seal  3   a , such that when the bag  10   a ′ is removed from the web  10   a , it can suitably retain contents placed therein. The pre-opening of each bag  10   a ′ occurs along the tear line  2   a  during manufacture by breaking the tear line  2   a  on one side of the bag  10   a ′ only near an open end  13   a . The side of each pre-opened bag  10   a ′ that is broken along the tear line  2   a  defines an open ply  50   a  and the side of each bag  10   a ′ that remains attached along the tear line  2   a  defines an attached ply  52   a . The open ply  50   a  and attached ply  52   a  each have respective insertion edges  51   a  and  53   a  at the open end  13   a  that are each defined as the side of each ply adjacent the tear line  2   a . Breaking the tear line  2   a  only along the open ply  50   a  forms a flap  4   a  at the open end  13   a  that defines an entry point into the pre-opened bag  10   a ′ through which produce or other items can be inserted without requiring removal of the bag  10   a ′ from the web  10   a . A small excess portion  14   a  of the open and attached plies  50   a  and  52   a  remains between the seal  3   a  and tear line  2   a  connecting the adjacent bag  10   a ′. At least a portion of the insertion edge  53   a  of the attached ply  52   a  remains connected to the tear line  2   a , thereby maintaining attachment of the bag  10   a ′ to an adjacent bag of the web  10   a  until intentionally detached by a user. 
   A vent  11  is located on the open ply  50   a  to facilitate the evacuation of air from the interior of the bag  10   a ′ during the manufacturing process. The vent  11  is located at a position on the open ply  50   a  that is adjacent the seal  3   a  and/or at the seal end  19   a  to minimize the amount of air that is trapped away from the insertion edge  53   a  of the open ply  50   a  as air is squeezed between the open ply  50   a  and attached ply  52   a . It will be appreciated that the vent  11  can also be positioned on the attached ply  52   a  or at any other location that is suitable for allowing air to escape from within the bag  10   a ′. The size and specific configuration of the vent  11  will be generally sufficient to securely prevent the loss of stored point-of-purchase items therethrough. It will be further appreciated that in some embodiments, the vent  11  can be omitted to allow for improved air tightness of the bag  10   a′.    
   Use of the bags  10   a  produced in accordance with the embodiment of the invention depicted in  FIG. 1  is intended to provide particular advantage in the specific venue of groceries, produce stores, supermarkets, etc., and in accordance with which, articles generally provided as bulk commodities and selected by a consumer at a point-of-purchase, and which items are routinely segregated by particular type for later unique pricing by weight or unit, may be conveniently packaged and brought to a register for checkout. Such advantageous use permits a user (i.e., most commonly a consumer) to at least partially fill a bag prior to removal from a web of plural bags, providing added convenience and shopping ease. 
   Although not intended to be limiting to the contemplated scope of the invention, bags produced in accordance with the invention can advantageously present dimensions between about 10″×14″ and about 12″ and 20″ (width×height), though some specific embodiments may have dimensions in the approximate range of 8″×10″ or smaller. Some embodiments of the invention may include pre-opened bags as larges as 14″w×24″h. In some embodiments of the invention, such dimensions can provide a suitable accommodating volume to meet the needs of a consumer utilizing the bags within the above-noted range of uses. In addition, although similarly not intended to be limiting to practice of the disclosed method in accordance with the invention, such pre-opened bags can be typically produced from either high or low density polyethylene, or like material, though high density polyethylene may be preferred for smaller bag thickness. A wall thickness of the bags of less than about 1.50 mils (thousandths of an inch) can for some applications be deemed advantageous to practice of the invention. In some typical application, an example wall thickness could lie in the approximate range of about 0.3 mils to about 0.9 mils. Within such a range, the use of a high density polyethylene may be preferred for bag thicknesses under about 0.7 mils. 
   Referring now to  FIG. 2 , a conversion machine  20  for manufacturing the bags  10   a ′ in accordance with the invention is schematically depicted. It is noted that the described production line utilizing the conversion machine  20  is disclosed merely as a production example of the bags  10   a ′ according to the invention, and it is not intended to be exhaustive of possible conventional and inventive machinery, and production methods, which could be employed with suitable effectiveness in achieving the objectives of the invention, without departure from the invention. 
   As shown in  FIG. 2 , a supply of raw material, for example extruded thermoplastic tubing (e.g. polyethylene, polypropylene, or any other suitable plastic material heretofore known or developed in the future, etc.), is fed from a payout roll  21  as a web  22  via feed and guide rollers  23 , using conventionally practiced transport and operational technology encountered in the typical manufacture of continuous plastic bags. The web of raw material  22  is directed to a rotating drum  24  about which the web  22  is contractably guided. A heat sealer  25  is moved radially inward to the drum  24  to contact the web of raw material  22  at intermittent intervals, and circumferentially follows a rotational movement of the drum  24  while in contact with the web  22 , thereby heat-sealing the web at a selected spaced apart distance determined by a desired bag height, and forming a seal that is generally the seal  3  shown in FIG.  1 . When brought out of contact with the web of raw material  22 , the heat sealer  25  is moved circumferentially backward to return the same to a starting position in anticipation of a subsequent sealing operation as described. 
   The web of raw material  22  next passes to a serrator  26  which includes a perforating blade  27  that rotates with the serrator  26  and contacts and perforates the web  22  drawn between the serrator  26  and a stationary support bar  28 . This allows for the formation of a perforation tear line  2  (see  FIG. 1 ) in the web  22  at a location there along adjacent to the previously formed seal  3 . 
   A scuffer section  29  is provided downstream of the serrator  26  for purposes of breaking the tear line  2  on one side of the web  22 . The scuffer section  29  includes a support, conveniently provided in the form of a rotating drum  29   a , and a scuffer pad assembly  29   b  that rotates counter-directional to rotating drum  29   a . The scuffer pad assembly  29   b  includes one or more scuffer pads  29   b ′ made of suitable material, for example, rubber, which presents sufficient friction to open the bags on only one side along the tear line  2 , and which intermittently contacts the web at the tear line  2  as the scuffer pad assembly  29   b  rotates. It will be understood that the pressure exerted by the scuffer pads  29   b ′ on the web  22  will be adjusted based upon various parameters including bag thickness, perforation characteristics, material thickness, etc., such that one side of the tear line  2  is broken, while the integrity of the tear line  2  on a remaining side distant from the scuffer pads  29   b ′, i.e. as attached to the insertion edge  53   a  of the attached ply  52   a  of  FIG. 1 , is at least partially maintained. 
   If a width of the bags  10   a ′ produced in accordance with the invention requires adjustment from that of the extruded tubing transported as the web of raw material  22 , a slit sealer  31  is provided which longitudinally slits and heat-seals the web  22  at a desired distance inwardly of the original outermost edge of the web of raw material  22 . 
   The web  22  is then subjected to an air test to establish that the bags  10   a ′ have been successfully scuffed open by utilizing a blower nozzle  32  that directs a stream of air to open the flap  4   a  (see also  FIG. 1 ) in the bags  10   a ′. Thereafter, the web  22 , which at this point has been converted into the continuously attached length of bags comprising the web  10  depicted in  FIG. 1 , is wound on to a pickup roll  33 . Excess air present in each bag  10   a ′ exits through the entrance to the bag  10   a ′, located at the insertion edge  53   a  of the open ply  50   a , and through the vent  11  as the web  22  is wound on to the pickup roll  33 . 
   Because of the particular configuration of the conversion machine  20  and the nature of transport of the web  22 , a further step is required to orient the flap  4  with respect to the supply roll  1   a  as shown in FIG.  1 . Referring now to  FIG. 3 , the pickup roll  33  serves as a payout roll when transferred to a rewinding station  40 , in which it is rewound onto a rewind roll  34 . As shown schematically, the flaps  4  are originally oriented such that the openings in the bags  10  would face downward if dispensed from the roll  33 . By rewinding the bags onto the rewind roll, the desired orientation is achieved, as shown in  FIG. 1 , in which roll  1   a  corresponds to that produced on rewind roll  34 . 
   It will be appreciated that other manufacturing processes are possible and it is contemplated that such other manufacturing processes can be used to construct pre-opened bags that are within the intended scope of the invention. In the course of manufacturing such pre-opened bags, some processes, including the one depicted in  FIGS. 2 and 3 , can be arranged to effect folding or misalignment of open plies. For example,  FIG. 4A  depicts a web  10   b  of pre-opened bags  10   b ′ in which the insertion edge  51   b  of each open ply  50   b  is capable, as shown in  FIG. 4A , of extending to a position that is substantially flush with the tear line  2   b.  Although capable of extending to this flush position at the open end  13   b , the insertion edge  51   b  will typically be at least partially and advantageously folded away from the tear line  2   b  with an adjacent bag  10   b ′ of the web  10   b.    
     FIG. 4B  depicts the web  10   b  of  FIG. 4A  in which an example of such partial folding of the insertion edge  51   b  from the tear line  2   b  is depicted. The result is the formation, at the open end  13   b  of the bag  10   b ′, of an open end fold  12  along a portion of the insertion edge  51   b . The open end fold  12  helps define the entry point of the bag  10   b ′ as defined by the flap  4   b  and facilitates further separation of the open and attached plies  50   b  and  52   b  as a user opens the pre-opened bag  10   b ′. The folding can be accomplished during the manufacturing process by causing the insertion edge  51   b  to momentarily catch air immediately after manufacturing of each bag  10   b ′ or later as the web  10   b  is wound from a payout roll to a pickup or rewind roll. Folding can also be effected by causing respective movement between the open ply  50   b  and attached ply  52   b  of each bag  10   b ′ such that gathering or bunching along the insertion edge  51   b  of the open ply  50   b  moves the open ply  50   b  toward a folded position. Depending on the specific plastic material being used to form the web  10   b , static electricity arising between adjacent layers of open and attached plies  50   b  and  52   b  can further contribute to folding motion. As a portion of the insertion edge  51   b  moves toward a folded position, the bag  10   b ′ is wound on to the supply roll  1   b , locking the moving portion of the insertion edge  51   b  to create the open end fold  12 . An unfolded portion  51   b ′ of the insertion edge  51   b  that does not catch air or otherwise fails to exhibit the folding motion may remain flush with the tear line  2   b  as the bag  10   b ′ is wound on to the supply roll  1   b  with the rest of the web  10   b . Additional agitation of the open ply  50   b  to effect folding can be provided with the placement of a fan, an additional air pressure nozzle, or other source of moving air placed in the vicinity of the web  10   b  during the manufacturing process. It is noted that such conditions will most effectively cause such folding where bags are larger than about 8″×10″ or where smaller material thicknesses, such as below about 1 mil, are used. For example, referring to the example manufacturing process depicted in  FIG. 2 , such folding can typically be expected to occur during the manufacturing of webs of bags comprised of high-density polyethylene (HDPE) film bags having a material thickness of 0.45 mils where each bag measures approximately 15 h″×12 w″ by placing an electric fan  49  approximately six inches from the pick-up roll  33 . 
   Depending on individual conditions during the manufacturing of each bag  10   b ′, larger or multiple open end folds  12  may be caused to form along the insertion edge  51   b  such as to reduce the extent of the unfolded portion  51   b ′ of the insertion edge  51   b . An example of this is depicted in  FIG. 4C , in which a bag  10   b ′ of the web  10   b  of  FIGS. 4A and 4B  is depicted to have multiple open end folds  12  that have formed along the insertion edge  51   b . Individual conditions leading to variations in the number, size, or orientation of open end folds  12  can depend on fluctuations or variations in surrounding air flow, equipment speed, ply structure, positioning, or other environmental, material, or equipment conditions that affect the manner in which individual bags  10   b ′ are manufactured. 
   In some embodiments, individual conditions can also lead to variations in folds near the seal of each bag.  FIG. 5A  depicts a web  10   c  of bags  10   c ′ in which each bag  10   c ′ includes a seal  3   c  that is separated from the tear line  2   c  to form an enlarged excess portion  14   c  on the open ply  50   c  having an excess edge  15 .  FIG. 5A  further depicts the enlarged excess portion  14   c  at the seal end  19   c  of the bag  10   c ′ on the open ply  50   c  extending from the seal  3   c  to a position in which the excess edge  15  is flush with the tear line  2   c.    
   The manufacturing process of this web  10   c  of pre-opened bags  10   c ′ can also be arranged to effect folding or misalignment of the excess portion  14   c  so that the excess portion  14   c  does not extend to a position where the excess edge  15  is flush or substantially flush with the tear line  2   b . As a result of such manufacturing processes, the excess portion  14   c  will typically be at least partially and advantageously folded away from the tear line  2   c  with an adjacent bag  10   c ′ of the web  10   c.    
     FIG. 5B  depicts the web  10   c  of  FIG. 5A  in which an example of such partial folding of the excess portion  14   c  is depicted. The result is one or more seal end folds  16  along a portion of the excess edge  15 . The one or more seal end folds  16  further help define the entry point into an adjacent bag  10   c ′ that is attached at the tear line  2   c , and further facilitates opening of the adjacent bag  10   c ′. Comparing  FIGS. 5B and 5C , one or more seal end folds  16  can form concurrently with the formation of one or more open end folds  12  (as depicted in FIG.  5 C), or in the absence of open end folds  12  (as depicted in FIG.  5 B). Individual conditions leading to variations in the number, size, orientation, or combination of seal end folds  16  with open end folds  12  can also depend on fluctuations or variations in surrounding air flow, equipment speed, ply structure, positioning, or other environmental, material, or equipment conditions that affect the manner in which individual bags  10   c ′ are manufactured. As best understood with reference to  FIG. 5D , it is also possible to have seal end folds  16  entirely absent on one bag  10   c ′ while one or more seal end folds  16  are present on an adjacent bag  10   c ′. Larger or multiple seal end folds  16  may also frequently form along the excess edge  15  such as to reduce the extent of the unfolded portion  15 ′ of the insertion edge  15 . 
   Like an open end fold  12  of an adjacent bag  10   c ′, a seal end fold  16  can be created during the manufacturing process by causing an excess edge  15  to momentarily catch air immediately after the manufacturing of each individual bag  10   c ′ or at a later time as the web  10   c  is wound from a payout roll to a pickup or rewind roll. Folding can also be effected by causing respective movement between the open ply  50   c  and attached ply  52   c  of each pre-opened bag  10   c ′ between the seal  3   c  and tear line  2   c  to create gathering or bunching along the excess edge  15  of the excess portion  14   c , moving the excess portion  14   c  toward a folded position. As with the open end fold  12 , static electricity can contribute to the formation of the seal end fold  16  depending on the specific material being used to form the web  10   c . Additional agitation of the open ply  50   b  to effect folding can be provided with the placement of a fan, an additional air pressure nozzle, or other source of moving air placed in the vicinity of the web  10   b  during the manufacturing process. It is noted that such conditions will most effectively cause such folding where bags are larger than about 8″×10″ or where smaller material thicknesses, such as below about 1 mil, are used. Referring again to the example manufacturing process depicted in  FIG. 2 , such folding can typically be expected to occur during the manufacturing of webs of bags comprised of high-density polyethylene (HDPE) film bags having a material thickness of 0.45 mils, where each bag measures approximately 15 h″×12 w″ and where the distance between the tear line and seal of each bag (excess portion length) measures between approximately 0.3″ and 0.5″, by placing an electric fan  49  approximately six inches from the pick-up roll  33 . 
   As one or more portions of the excess edge  15  move toward a folded position, the bag  10   c ′ is wound on to the supply roll  1   c , locking the folding portion of the excess edge  15  to create the seal end fold  16 . Any unfolded portion  15 ′ of the excess edge  15  that does not catch air or otherwise fail to exhibit the folding motion may remain flush with the tear line  2   c  as the bag  10   c ′ is wound on to the supply roll  1   c  with the rest of the web  10   c . In some circumstances, the entire excess portion  14   c  may remain in a position such that the entire excess edge  15  remains substantially flush with the tear line  2   c , as depicted in FIG.  5 A and with the topmost of the unrolled pre-opened bags  10   c ′ in  FIG. 5D , though generally, at least one of the excess edge  14  or insertion edge  51   c  will fold over and act as a visual indication of the point of entry into the pre-opened bag  10  at the open end  13   c.    
   Additional visual indicators of the point of entry into the pre-opened bag  10  are also possible and contemplated to be within the scope of the invention.  FIG. 6  depicts a web  10   d  of pre-opened bags  10   d ′ that is similar to the web  10   c  of pre-opened bags  10   c ′ depicted in  FIGS. 5A-D , the slightly altered view depicting the flap  4   d  of the open ply  50   d  when it is separated from the attached ply  52   d  such that the point of entry into the pre-opened bag  10   d ′ at the open end  13   d  is clearer to the open eye. Such separation between the flap  4   d  and attached ply  52   d  can be effected mechanically either during or after the manufacturing process as, for example, with blown air as in the possible manufacturing method described in the above description of  FIGS. 2 and 3 . The user can also effect separation manually at a later time. Such separation will generally begin to eliminate any existing open end fold that is present along the insertion edge  51   d.    
     FIG. 7  depicts a possible visual indicator of the point of entry into each pre-opened bag  10   e ′ of a web  10   e  in which the color of each open ply  50   e  is different from the color of the attached ply  52   e . If either the insertion edge  51   e  or excess edge  15  of an adjacent bag are folded to create an open end fold or seal end fold, a portion of the attached ply  52   e  will be visible when looking toward the open ply  50   e  of the bag  10   e ′ due to the color contrast between the plies. Normally, this color contrast will also be visible if the flap  4   e  of the open ply  50   e  is separated from the attached ply  52   e , allowing for a quick visual determination of the location of the point of entry to the bag  10   e ′ at the open end  13   e.    
     FIG. 8  depicts a web  10   f  of pre-opened bags  10   f  that include visual indicators each comprising an indicator stripe  18  at the open end  13   f . Each indicator stripe  18  can be formed from an ink or print line, sticker, other adhesive composition or impregnated coloration that is a contrasting color to the color of the open ply  52   f . An indicator stripe  18  is normally positioned along the open ply  52   f  to follow the insertion edge  51   f . When there is respective movement between the open ply  50   f  and attached ply  52   f , such as when the bag  10   f  is grasped or pinched by the user, the indicator stripe generally moves with the insertion edge  51   f , emphasizing the moving location of the point of entry to the bag  10   f′.    
   In some embodiments, an additional indicator can be used to assist the user in locating an appropriate grasping or pinching location to effect dispensing and further opening of a bag.  FIG. 9A  depicts a web  10   g  of pre-opened bags  10   g ′ having a thumb icon indicator  17  that is printed on the open ply  50   g  of each bag  10   g ′ adjacent the seal  3   g  at the seal end  19   g  to denote an appropriate location for grasping and pulling on the pre-opened bag  10   g ′. As shown, the thumb icon indicator  17  comprises an image of a human thumb, though it will be appreciated that other images denoting an appropriate grasping or pulling location can also be printed or adhered to a visible location of the open ply  50   g . In the depicted embodiment, the thumb icon indicator  17  suggests to the user that the appropriate location for grasping the bag pre-opened  10   g ′ is at the seal end  19   g  of the bag  10   g ′ near the seal  3   g . The hand  5  of the user approaches from beneath the bag  10   g ′ to be dispensed so that the user&#39;s index finger  7  and middle finger  8  contact the attached ply  52   g  while the user&#39;s thumb  6  contacts the open ply  50   g  at the thumb icon indicator  17 . 
   Comparing  FIG. 9A  with  FIG. 9B , the user pinches the pre-opened bag  10   g ′ with the index finger  7 , middle finger  8 , and thumb  6 . A slight relative movement between the index finger  7  and middle finger  8  with the thumb  6  causes a slight relative movement between the open ply  50   g  and attached ply  52   g  that results in the formation of gathering  9  along the surface of the open ply  50   g . Referring now to  FIG. 9   b , this gathering  9  tends to pull the insertion edge  53   g  of the open ply  50   g  downward and away from the tear line  2   g , further visually indicating the point of entry into the pre-opened bag  10   g ′ at the open end  13   g  and serving to further open the bag  10   g ′. Such icon indicators  17  can be used in conjunction with other visible indicators of the point of entry into each bag  10   g ′, such as those depicted in  FIGS. 5B-D ,  7 , and  8 , and as described above, to further facilitate bag opening and use. 
   The invention has been shown and described in various embodiments in which a web of bags is stored on a supply roll and dispensed to allow the seal of a first bag to lead off of the roll to allow the insertion edge of an open ply to be adjacent a tear line connecting the first bag to a second bag that is further from the end of the web (i.e., further away from being dispensed). In some embodiments, this allows a user to at least partially fill a bag prior to removal from the web. However, it will be appreciated that in some embodiments and under some circumstances of use, it may be advantageous to configure the invention to allow the insertion edge of an open ply of a second bag to lead off of the roll, allowing the seal of the second bag to be adjacent a tear line separating the second bag with a first bag. As an example of such a configuration,  FIG. 10  depicts the web  10   a  of bags  10   a ′ of  FIG. 1  prior to being transferred to a rewind roll  34  of the rewinding station  40 . Such a configuration could also be achieved by again rewinding the rewind roll  34  of the web  10   a  in  FIG. 3  on to a secondary rewind roll (not shown) or otherwise reversing the dispensing order of subsequent pre-opened bags  10   a ′ of the web  10   a  as required by the specific circumstances of use. 
   The invention can be used in conjunction with a storage form to further facilitate bag opening by increasing tension as individual bags are dispensed from a supply roll. Many such embodiments of the invention will include a locking device such as a ratchet, core-lock, tightly mounted supply roll, or similar device to increase tension. 
     FIG. 11A  depicts one embodiment of a storage form  35   h  in which a supply roll  1   h  is mounted on a dispensing rack  37   h . A step ratchet  36  includes a flexible pawl  38   h  mounted to the supply roll  1   h  and positioned to engage multiple, evenly spaced ratchet teeth  39   h  that extend inward from the inside surface of the supply roll  1   h . The pawl  38   h  is curved to allow the supply roll  1   h  to rotate in one direction only. When a user pulls a bag  10   h ′ from the supply roll  1   h , the step ratchet  36  produces minor hesitations, or incremental tensional increases against the force of the pulling action as the supply roll  1   h  rotates about its axis  40 . The number of hesitations that occur during a single complete rotation of the supply roll  1   h  depends on the number of ratchet teeth  39   h  that are present within the supply roll  1   h . As the user continues to pull a bag  10   h ′ from the web  10   h , the increased tension of each hesitation serves to cause further relative movement between the open and attached plies of the bag  10   h ′ being dispensed, further defining the entry point into the bag  10   h ′ at the open end  13   h . Depending on the magnitude of the pulling force exerted by the user, the hesitations can also aid in detachment of the bag  10   h ′ from the web  10   h.    
     FIG. 11B  depicts an embodiment storage form  35   i  in which a supply roll  1   i  is mounted on a dispensing rack  37   i  that incorporates an inertial ratchet  40 . The inertial ratchet  40  includes a flexible pawl  38   i  mounted to a dispensing rack  37   i  and positioned to engage a single ratchet tooth  39   i  that extends inward from one point along the inside surface of the supply roll  1   i . The pawl  38   i  is curved to allow the supply roll  1   i  to rotate in one direction only. 
   When a user pulls a pre-opened bag  10   i ′ from the supply roll  1   i , the inertial ratchet  36  allows the supply roll  1   i  to rotate by as much as one complete rotation before exerting a tensional increase or hesitation against the pulling force of the user. In some embodiments, the length of a bag  10   i ′ of the web  10   i  will be on the order of one arc length of the supply roll  1   i , depending on the number of pre-opened bags  10   i ′ that remain on the roll  1   i . As the user continues to pull the bag  10   i ′, the supply roll  1   i  rotates about its axis  40   i , accumulating angular momentum. Once the pawl  38   i  strikes the ratchet tooth  39   i , the sudden hesitation of the rotation of the roll  1   i  contrary to its accumulated angular momentum serves to cause further relative movement between the open and attached plies of the pre-opened bag  10   i ′ being dispensed, further defining the entry point into the bag  10   i ′. Depending on the magnitude of the pulling force exerted by the user and/or the total accumulated momentum of the rotating supply roll  1   i , the sudden hesitation can also aid in detachment of the pre-opened bag  10   i ′ from the web  10   i.    
   The invention can also be configured with a storage form that constantly increases tension by continuously increasing resistance against rotation of the supply roll. For example,  FIG. 12  depicts a storage form  35   j  that includes a storage rack  37   j  inserted tightly into the supply roll  1   j . The tight insertion of the storage rack  37   j  causes substantial frictional resistance between the outside rolled surface of the storage rack  37   j  and inside rolled surface of the supply roll  1   j  as the roll  1   j  rotates about its axis  40   j . As the user continues to pull a pre-opened bag  10   j ′ from the web  10   j , the constant increased tension serves to cause further relative movement between the open and attached plies of the bag  10   j ′ being dispensed, further defining the entry point into the bag  10   j ′ and possibly aiding in detachment of the bag  10   j ′ from the web  10   j.    
     FIGS. 13A and B  depict a storage form  35   k  having a core lock  41  for insertion into either end of a supply roll  1   k . The core lock  41  includes multiple inward extending, flexible ribs  42  positioned in pairs around the rolled inside surface  43  of the core lock  41 . As best understood from the exploded view of the storage form  35   k  in  FIG. 13A , the rolled outside surface  44  of each core lock  41  is dimensioned to fit tightly within the supply roll  1   k . A tapered end  45  allows each core lock  41  to be inserted in an end of the supply roll  1   k  notwithstanding the tight fit. A stop flange  46  forms a slightly enlarged diameter at one end of the core lock  41  to restrict further insertion once the core lock  41  is fully inserted within the supply roll  1   k . Once each core lock  41  is inserted into each end of the supply roll  1   k , the tight fit is generally sufficient to prevent significant relative movement between the core lock  41  and roll  1   k.    
   The flexible ribs  42  of the core lock  41  are each sufficiently thin and extend sufficiently inward from the rolled inside surface  43  to allow for engagement with the storage rack  37   k  when the storage rack  37   k  is inserted through the core lock  41  and supply roll  1   k  along the axis  40   k . As best understood with reference to the side view of  FIG. 13B , the cross sectional diameter of the storage rack  37   k  is slightly greater than the inside core lock clearance created by the inward reach of the ribs  42 , causing slight flexible bending  48  at the tip of each rib  42  as the storage rack  37   k  is inserted into the supply roll  1   k . The combined flexing of the multiple ribs  42  serves to securely position the storage rack  37   k  at an approximately centered position with respect to the core lock  41  and supply roll  1   k . Generally, either the ribs  42 , storage rack  37   k , or both are constructed of a material having a low coefficient of friction. The combined contact between the flexible ribs  42  and rack  37   k  is also very small compared to the contact area between the core lock  41  and supply roll  1   k , which is approximately equal to the total rolled outside surface  44  of the core lock  41 . As best viewed in  FIG. 13A , the combined contact between the flexible ribs  42  and rack  37  is further reduced by the addition of a reduction notch  47  across each rib  42 . 
   It will further be appreciated that in some embodiments, a core lock can be integrated directly into the structure of a supply roll with each rib extending inwardly and directly from an inside surface of the supply roll structure in order to increase tension against a storage rack. 
   Due to this substantial differential of friction, the core lock  41  will normally rotate with the supply roll  1   k  about the axis  40   k  when a user pulls an individual pre-opened bag  10   k ′ from the web  10   k , the flexible ribs  42  of the core lock  41  sliding along the outside rolled surface of the storage rack  37   k . However, the amount of friction between the ribs  42  and storage rack  37   k  is generally sufficient to significantly increase constant tension to cause further relative movement between the open and attached plies of the pre-opened bag  10   k ′ being dispensed, further defining the entry point into the bag  10   k ′ and possibly aiding in detachment of the bag  10   k ′ from the web  10   k.    
   Having described preferred embodiments of the invention with reference to the accompanying drawings, it is to be understood that the invention is not limited to those precise embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims.