Abstract:
A polyethylene produce bag roll includes a plurality of plastic film bags joined to one another with a perforation line. The perforation line is slit at at least one end for a first predetermined distance to aid in tearing the bag from the roll. The perforation may also include a chisel cut to aid in removing bags from the roll in a dispenser equipped with a perforation parting means. The bags may be gusseted or ungusseted. Outer surfaces of the bags are corona treated to enhance adhesion of printing ink to the bags. The bag roll may be cored or uncored.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
       [0001]     This application is a Divisional of U.S. patent application Ser. No. 10/850,485, filed May 20, 2004, now allowed. 
     
    
     FIELD OF INVENTION  
       [0002]     The invention pertains to plastic bags. More particularly, the invention relates to plastic bags designed for fresh produce that are dispensed from compact rolls and designed to be easily opened.  
       BACKGROUND OF THE INVENTION  
       [0003]     Plastic bags have found wide use in grocery markets and retail applications for transporting produce groceries and various other items. To be most useful for consumers plastic bags should incorporate a number of features. These features relate to the ease of use of the bags with respect to tearing them from a bag roll, opening them, placing goods inside, carrying them and dispensing them.  
         [0004]     A variety of designs have been developed to meet these needs. U.S. Pat. No. 5,215,275, issued to Gold, is directed to a process for making a roll of plastic bags such as those used in the produce section of a supermarket. The plastic bag roll is made from a film extruded in the form of a tube and slit into two parallel faces. The two-ply web of material is then sub-divided into a series of interconnected plastic bags. The bottom of each bag is formed by a transverse seal extending from one side of the web to the other. Below seal, each ply of the web is perforated separately to prevent sticking. The perforation lines of the two plies coincide at the nips that facilitate tearing a bag from the roll. After perforation, the sides of the web are heat sealed to form the bag. The finished roll of bags is wound about a dowel or cardboard tube.  
         [0005]     U.S. Pat. No. 4,652,253, issued to Benoit, is directed to a method for forming a roll of gusseted flat bottom thermoplastic bags. A tube of typically polyethylene film is collapsed and simultaneously gusseted yielding gussets that do not fully extend to the vertical center of the tube. A seal line and perforation line are then simultaneously formed. Triangular regions bounded by the sealed and severed line, the cut line and the edge of the gusset are then removed from the tube. The formed bags are wound into a roll interconnected at the perforation lines.  
         [0006]     U.S. Pat. No. 5,971,138, issued to Soughan, is directed to a toiletry-dispensing package. A roll of envelopes formed of flexible polymeric moisture-resistant film material is shown. These envelopes are separated by perforation lines extending across the width of the roll. The end points of perforation line coincide with nips or cuts.  
         [0007]     U.S. Pat. No. 4,802,582, issued to Johnson, is directed to a roll of continuous draw tape plastic bags. The bags are interconnected laterally by perforation lines bounded by side seals. The side welds of adjacent bag tape hems form a notch at the end point of the perforation line. seals. The side welds of adjacent bag tape hems form a notch at the end point of the perforation line.  
         [0008]     U.S. Pat. No. 4,747,815, issued to Benoit et al., is directed to a collection of thin thermoplastic bags meant for grocery produce. Lines of weakness are formed transversely across each film face for bag tear-off. Both faces of the bag have a series of similar perforations beneath the seal. In an alternate embodiment the front face of the bag has a series of perforations interrupted in the center by a slit approximately one-third the width of the bag. In another embodiment the perforations on the front bag face are interrupted by a cutout. Both the slit and the cutout accommodate opening of the bag mouth and removing the bag.  
         [0009]     It is an objective of the present invention to provide plastic bags that can be easily stored on and dispensed from various roll dispensers. It is a further objective to provide bags that can be easily torn from a dispensing roll. It is a still further objective of the invention to provide bags that can be easily manufactured in gusseted or ungusseted form. Finally, it is an objective to provide roll mounted bags that are easily opened after dispensing and that are easily removed from the roll.  
         [0010]     While some of the objectives of the present invention are disclosed in the prior art, none of the inventions found include all of the requirements identified.  
       SUMMARY OF THE INVENTION  
       [0011]     The present invention addresses all of the deficiencies of plastic bag roll inventions and satisfies all of the objectives described above.  
         [0012]     (1) A pre-cut plastic bag roll providing the desired features may be constructed from the following components. A continuous web of plastic bags formed from polyethylene material is provided. Each bag has a front wall and a rear wall. The front wall has an inner surface, an outer surface, first and second side edges, a top edge and a bottom edge. The rear wall has an inner surface, an outer surface, first and second side edges, a top edge and a bottom edge. The front wall is joined to the rear wall at their respective first and second side edges. The front wall is sealed to the rear wall adjacent at their respective bottom edges. An open mouth is located at the top edges of the front and rear walls. The front and rear walls of each of the bags is removably attached by a perforation line at the bottom edges to the top edges of a subsequent bag in the web. The perforation line has a first end and a second end. The perforation line is slit inwardly from at least one of the first and second ends for a predetermined distance. The web is rolled to form a bag roll.  
         [0013]     (2) In a variant of the invention, a chisel cut is provided. The chisel cut extends through a center point of the perforation line of the web. When the roll is installed in a bag dispenser the chisel cut will engage a separating tongue when bags are pulled from the roll.  
         [0014]     (3) In another variant, the web is rolled about a core.  
         [0015]     (4) In still another variant, the bags have at least one side gusset. The side gusset extends inwardly from either of the first and second side edges of the front and rear walls.  
         [0016]     (5) In a further variant, the side gusset extends inwardly from either of the first and second side edges of the front and rear walls for up to one third of a width of the bags.  
         [0017]     (6) In still a further variant, the side gusset extends inwardly from either of the first and second side edges of the front and rear walls for up to one half of a width of the bags.  
         [0018]     (7) In yet a further variant, the outer surface of at least one of the front wall and the rear wall of the bags is corona treated.  
         [0019]     (8) In still a further variant, the corona treatment of the outer surface of at least one of the front and rear walls of each of the bags is an amount sufficient to result in a surface tension on the wall of at least about 38 dynes/cm.  
         [0020]     (9) In another variant of the invention, the outer surface of at least one of the front wall and the rear wall of the bags is printed.  
         [0021]     (10) In still another variant, a method of making a pre-cut plastic bag roll, has the following steps: Extruding a tube of polyethylene material. Flattening the tube to form a continuous web having upper and lower surfaces and first and second side edges. Sealing the tube perpendicular to the first and second side edges at predetermined intervals to form bag bottoms. Perforating the continuous web perpendicular to the first and second side edges to form a perforation line where the perforation line has a first end and a second end. Slitting the perforation line inwardly from at least one of the first and second ends for a first predetermined distance. Rolling the web into a bag roll.  
         [0022]     (11) In yet another variant, the method of making a pre-cut plastic bag roll includes the further step of chisel cutting the web at a center point of the perforation line prior to rolling the web into a bag roll.  
         [0023]     (12) In still another variant, the method of making a pre-cut plastic bag roll includes the further step of providing a bag roll core prior to rolling the web into a bag roll.  
         [0024]     (13) In a further variant the method of making pre-cut plastic bag roll includes the further step of gusseting the tube of polyethylene material prior to flattening the tube to form a continuous web.  
         [0025]     (14) In still a further variant, the method of making a pre-cut plastic bag roll includes the further step of corona treating at least one of the upper and lower surfaces of the continuous web prior to sealing the tube perpendicular to the first and second side edges.  
         [0026]     (15) In another variant of the invention, the method of making a pre-cut plastic bag roll includes the further step of printing either of the upper and lower surfaces of the continuous web after corona treatment.  
         [0027]     (16) In still another variant, an apparatus for making a pre-cut plastic bag roll includes the following components. A supply of polyethylene material is provided. An extruder is provided. The extruder forms a continuous tube of thin film polyethylene. A tubing flattener is provided. The flattener flattens the continuous tube into a continuous bag web. A sealer is provided. The sealer forms a series of seals in the bag web perpendicular to a long axis of the web. A perforator is provided. The perforator perforates the bag web through two film layers and forms a perforation line and a slit. A bag roller is provided. The bag roller rolls the perforated bag web into a compact roll.  
         [0028]     (17) In yet another variant, the apparatus includes a chisel cutter. The chisel cutter forms a chisel cut through the two film layers at a center point of the perforation line.  
         [0029]     (18) In a further variant, the apparatus includes a supply of cores. The bag web is wound around the cores to form the bag rolls.  
         [0030]     (19) In still a further variant, the apparatus includes a gusseter. The gusseter forms at least one side gusset in the continuous tube prior to flattening.  
         [0031]     (20) In still a further variant of the invention, the apparatus includes a corona treater. The corona treater corona treats at least one of the upper and lower surfaces of the continuous bag web prior to rolling.  
         [0032]     (21) In a final variant, the apparatus includes a printer. The printer prints on at least one of the upper and lower surfaces of the continuous bag web after corona treatment.  
         [0033]     An appreciation of the other aims and objectives of the present invention and an understanding of it may be achieved by referring to the accompanying drawings and the detailed description of a preferred embodiment. 
     
    
     DESCRIPTION OF THE DRAWINGS  
       [0034]      FIG. 1  is a perspective view of the bag roll of the preferred embodiment of the invention illustrating the cut at one end of the perforation line;  
         [0035]      FIG. 2  is a perspective view of an apparatus for making the  FIG. 1  embodiment;  
         [0036]      FIG. 3  is a perspective view of the  FIG. 1  embodiment illustrating the bag opening;  
         [0037]      FIG. 4  is a perspective view of a detail of the  FIG. 1  embodiment illustrating cut at one end of the perforation line; and  
         [0038]      FIG. 5  is a perspective view of an apparatus for making a second, gusseted embodiment of the pre-cut bag; and  
         [0039]      FIG. 6  is a perspective view of the second embodiment illustrating the bag opening and side gussets. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0040]     (1)  FIGS. 1, 3  and  4  illustrate a pre-cut plastic bag roll  10  providing the desired features that may be constructed from the following components. A continuous web  15  of plastic bags  20  formed from polyethylene material is provided. Each bag  20  has a front wall  25  and a rear wall  30 . The front wall  25  has an inner surface  35 , an outer surface  40 , first  45  and second  50  side edges, a top edge  55  and a bottom edge  60 . The rear wall  30  has an inner surface  65 , an outer surface  70 , first  75  and second  80  side edges, a top edge  85  and a bottom edge  90 . The front wall  25  is joined to the rear wall  30  at their respective first  45 ,  75  and second  50 ,  80  side edges. The front wall  25  is sealed to the rear wall  30  adjacent their respective bottom edges  60 ,  90 . An open mouth  95  is located at the top edges  55 ,  85  of the front  25  and rear  30  walls. The front  25  and rear  30  walls of each of the bags  20  is removably attached by a perforation line  100  at the bottom edges  60 ,  90  to the top edges  55 ,  85  of a subsequent bag  20  in the web  15 . The perforation line  100  is straight, and has a first end  105  and a second end  110 . The perforation line  100  is slit inwardly from at least one of the first  105  and second  110  ends for a predetermined distance  115 , which is greater than the length of a single perforation. The web  15  is rolled to form a bag roll  10 .  
         [0041]     (2) In a variant of the invention, a chisel cut  120  is provided. The chisel cut  120  extends through a center point  125  of the perforation line  100  of the web  15 . When the roll  10  is installed in a bag dispenser (not shown) the chisel cut  120  will engage a separating tongue (not shown) when bags  20  are pulled from the roll  10 .  
         [0042]     (3) In another variant, the web  15  is rolled about a core  140 .  
         [0043]     (4) In still another variant, as illustrated in  FIG. 6 , the bags  20  have at least one side gusset  145 . The side gusset  145  extends inwardly from either of the first  45 ,  75  and second  50 ,  80  side edges of the front  25  and rear  30  walls.  
         [0044]     (5) In a further variant, the side gusset  145  extends inwardly from either of the first  45 ,  75  and second  50 ,  80  side edges of the front  25  and rear  30  walls for up to one third of a width  150  of the bags  20 .  
         [0045]     (6) In still a further variant, the side gusset  145  extends inwardly from either of the first  45 ,  75  and second  50 ,  80  side edges of the front  25  and rear  30  walls for up to one half of a width  150  of the bags  20 .  
         [0046]     (7) In yet a further variant, the outer surface  40 ,  70  of at least one of the front wall  25  and the rear wall  30  of the bags  20  is corona treated.  
         [0047]     (8) In still a further variant, the corona treatment of the outer surface  40 ,  70  of at least one of the front  25  and rear  30  walls of each of the bags  20  is an amount sufficient to result in a surface tension on the wall  25 ,  30  of at least about  38  dynes/cm.  
         [0048]     (9) In another variant of the invention, the outer surface  40 ,  70  of at least one of the front wall  25  and the rear wall  30  of the bags  20  is printed.  
         [0049]     (10) In still another variant, as illustrated in  FIGS. 2 and 5 , a method of making a pre-cut plastic bag roll  10 , has the following steps: Extruding a tube  155  of polyethylene material. Flattening the tube  155  to form a continuous web  15  having upper  160  and lower  165  surfaces and first  170  and second  175  side edges. Sealing the tube  155  perpendicular to the first  170  and second  175  side edges at predetermined intervals  180  to form bag bottoms  185 . Perforating the continuous web  15  perpendicular to the first  170  and second  175  side edges to form a straight perforation line  100  where the perforation line  100  has a first end  105  and a second end  110 . Slitting the perforation line  100  inwardly from at least one of the first  105  and second  110  ends for a first predetermined distance  115 , which is greater than the length of a single perforation. Rolling the web  15  into a bag roll  10 .  
         [0050]     (11) In yet another variant, the method of making a pre-cut plastic bag roll  10  includes the further step of chisel cutting the web  15  at a center point  125  of the perforation line  100  prior to rolling the web  15  into a bag roll  10 .  
         [0051]     (12) In still another variant, the method of making a pre-cut plastic bag roll  10  includes the further step of providing a bag roll core  140  prior to rolling the web  15  into a bag roll  10 .  
         [0052]     (13) In a further variant, the method of making pre-cut plastic bag roll  10  includes the further step of gusseting the tube  155  of polyethylene material prior to flattening the tube  155  to form a continuous web  15 .  
         [0053]     (14) In still a further variant, the method of making a pre-cut plastic bag roll  10  includes the further step of corona treating at least one of the upper  160  and lower  165  surfaces of the continuous web  15  prior to sealing the tube  155  perpendicular to the first  170  and second  175  side edges.  
         [0054]     (15) In another variant of the invention, the method of making a pre-cut plastic bag roll  10  includes the further step of printing either of the upper  160  and lower  165  surfaces of the continuous web  15  after corona treatment.  
         [0055]     (16) In still another variant, an apparatus  195  for making a pre-cut plastic bag roll  10  includes the following components. A supply of polyethylene material (not shown) is provided. An extruder (not shown) is provided. The extruder forms a continuous tube  155  of thin film polyethylene. A tubing flattener  210  is provided. The flattener  210  flattens the continuous tube  155  into a continuous bag web  15 . A sealer  215  is provided. The sealer  215  forms a series of seals  220  in the bag web  15  perpendicular to a long axis  225  of the web  15 , at predetermined intervals  180 . A perforator  230  is provided. The perforator  230  perforates and slits the bag web  15  through two film layers  25 ,  30  and forms a straight perforation line  100  and a slit  105 . The slit  105  has a length  115 , which is greater than the length of a single perforation. A bag roller (not shown) is provided. The bag roller rolls the perforated bag web  15  into a compact roll  10 .  
         [0056]     (17) In yet another variant, the apparatus  195  includes a chisel cutter  240 . The chisel cutter  240  forms a chisel cut  120  through the two film layers  25 ,  30  at a center point  125  of the perforation line  100 .  
         [0057]     (18) In a further variant, the apparatus  195  includes a supply of cores  140 . The bag web  15  is wound around the cores  140  to form the bag rolls  10 .  
         [0058]     (19) In still a further variant, the apparatus includes a gusseter  245 . The gusseter  245  forms at least one side gusset  145  in the continuous tube  155  prior to flattening.  
         [0059]     (20) In still a further variant of the invention, the apparatus  195  includes a corona treater  250 . The corona treater  250  corona treats at least one of the upper  160  and lower  165  surfaces of the continuous bag web  15  prior to rolling.  
         [0060]     (21) In a final variant, the apparatus  195  includes a printer  255 . The printer  255  prints on at least one of the upper  160  and lower  165  surfaces of the continuous bag web  15  after corona treatment.  
         [0061]     The pre-cut plastic bag roll  10 , method and apparatus  195  have been described with reference to particular embodiments. Other modifications and enhancements can be made without departing from the spirit and scope of the claims that follow.