The present invention relates to a packaging apparatus for feeding and loading individual bags formed in a continuous strip in which successive bags are connected end-to-end. More specifically, the present invention relates to a fully electric packaging apparatus that includes an integrated printer assembly that is pivotable away from the drive rollers used to feed the continuous strip of bags, wherein the integrated printer assembly prints a label or product marking on each of the bags in the continuous strip immediately prior to the printed bag being loaded with the product being packaged.
Currently, many manufacturers utilize automated loading machines to load products to be packaged into individual plastic bags. The plastic bags are typically contained in a xe2x80x9cwicketxe2x80x9d in which successive bags are stacked on top of each other and held in alignment by a header having a series of wicket rods. Once each bag is filled with the product to be packaged, the bag is torn along a line of perforation and separated from the header that aligns the stack of bags. After the bag has been filled with the product, the bag is transferred to a drop sealer in which the two layers of plastic forming the bag are heat sealed in a conventional manner. Although the combination of a wicketed bag loading machine and a drop sealer is in wide use and has proven to be effective, drawbacks exist in the use of plastic bags stacked in the wicket package.
One such drawback is the limitation in the type of printing that can be applied to the individual bags in the wicket. Since the bags in the wicket are stacked on top of each other and are loaded with a product while still attached to the wicket header, there is no possibility of printing a design on the plastic bag prior to the insertion of the product. Although the wicketed bags could be printed prior to assembly into the wicketed packet, the manufacturer of the wicketed bags typically mass produces the bags without customizing the bags for the individual customer. Thus, if the customer wishes to imprint information on the bags after purchase from the manufacturer, the wicketed bags must be imprinted after the product has been loaded and the wicketed bag sealed by the drop sealer. If the product being sold in the sealed plastic bags includes an irregular surface, printing after the bag has been filled can prove to be a difficult and imprecise proposition.
Recently, continuous strips of bags that are end connected have become available for use in packaging products. Each of the bags in the continuous strip includes an open end that is connected to the closed end of the next bag in the continuous strip. Rolls of continuous strip bags can include at least 1000 bags. However, the automated feeding and loading of the continuous strip of bags has also presented problems in the feeding of the bags from the supply source and the opening of the bags in the continuous strip prior to loading of the products to be packaged.
In currently available packaging apparatus that open and load continuous strips of bags that are end connected, the printing on each bag is done by a printer that is typically located upstream from the location at which the printed bag is loaded with the product being packaged. Although an upstream printer is adequate when loading identical products into bags such that the printing on each individual bag does not have to correspond to the particular product being packaged, drawbacks exist if the bag feeding and loading apparatus is used to package products that are specialized and require specific labeling for the product being packaged. For example, if the bag feeding and loading apparatus is used to package medical prescriptions for individual patients, it is critical that the information printed upon each individual bag matches the product being placed within the bag. In a feeding and loading apparatus in which several cycles of the apparatus take place between the printing of an individual bag and the loading of the same bag, an opportunity exists for misalignment between the printed product packaging and the actual product being inserted therein.
In addition to the possible misidentification that can occur due to the number of bags positioned between the bag being loaded and the bag being printed, the printed bags extending between the loading area and the printing area result in wasted product during changeovers from bag types or the type of printing being placed upon the bag. In many cases, as many as four to six bags can be wasted during each changeover.
Another drawback that exists in currently available packaging apparatus is the number of rollers and drive assemblies required to operate both the printer and the bag drive assembly. In addition to the increase in number of parts and cost, the complex path through which the continuous strip of bags travels increases the amount of time required to load a new strip of bags into the packaging apparatus. Further, the multiple drives require complicated timing arrangements to insure that the bag feeding and printer assembly operate at the same speed in order to position the printed material on the bag in the correct location.
Therefore, it is an object of the present invention to provide an apparatus that can be used to print, feed and seal individual bags with increased accuracy. Further, it is an object of the present invention to provide such an apparatus that allows an article to be positioned into the bag immediately following the printing of the bag by the integrated printing assembly. Further, it is an object of the present invention to position the printing assembly directly above the bag feeding assembly. It is an additional object of the invention to provide a printer assembly that can be rotated away from the bag drive assembly to increase the ease of loading of the continuous strip of bags. Further, it is an object of the present invention to provide a fully electronic apparatus that requires no compressed air to operate.
The present invention is a packaging apparatus for feeding, printing and sealing a bag from a continuous strip of bags. The packaging apparatus of the present invention is particularly desirable in presenting individual bags for loading individualized products into successive bags where each of the bags must be individually printed with information specifically related to the product being placed within the bag.
The packaging apparatus of the present invention includes a bag feeding assembly mounted to a stationary support frame. The bag feeding assembly receives the continuous strip of bags from a supply roll that is mounted to a bag tensioning assembly. The continuous strip of bags passes over a drive roller that is operable to pull the continuous strip of bags from the supply roll.
The bag feeding assembly further includes a platen roller positioned adjacent to the drive roller. Both the drive roller and the platen roller are commonly driven by an electric drive motor. The electric drive motor is coupled to the drive roller and the platen roller through a belt assembly such that both the drive roller and the platen roller are rotated at a common speed.
After the continuous strip of bags passes over the bag feeding assembly, the continuous strip of bags is received by a bag sealing assembly. The bag sealing assembly is operable to seal the open mouth of each bag after the bag has been loaded with a product.
The bag sealing assembly includes a pressure bar mounted between a pair of spaced side arms. The pressure bar includes a anvil plate that presses the open end of the bag into a heated wire to seal the open mouth of each bag after the bag has been loaded. Each of the side arms of the bag sealing assembly is movable toward and away from the stationary support frame of the packaging apparatus.
Specifically, each of the side arms includes a rack member that receives a rotatable drive gear. The pair of spaced drive gears are connected by a shaft that is rotatably driven by an electric drive motor. As the electric drive motor rotates, the teeth of the drive gears engage the spaced rack members to move the side arms of the bag sealing assembly into and out of the support frame. In this manner, the entire bag sealing assembly is fully electric.
The bag tensioning assembly of the packaging apparatus includes a support shaft that extends through the hollow core of the supply roll. The rotatable support shaft includes a bias member positioned to exert a rotational bias force on the support shaft. Specifically, as bags are unwound from the supply roll, the rotating shaft loads the bias member. When tension created by the feeding assembly is removed from the continuous strip of bags, the bias member exerts a rotational bias force on the supply roll to rewind the continuous strip of bags and maintain the proper tension on the continuous strip of bags.
In a first embodiment of the invention, the bias member of the bag tensioning assembly is a torsion spring having a first end coupled to the support shaft and a second end coupled to a slip clutch. As the support shaft rotates when the continuous strip of bags are withdrawn from the supply roll, the slip clutch operates to maintain the desired load on the torsion spring. Specifically, the inner race of the slip clutch is coupled to an adjustment spring that sets the amount of tension required on the torsion spring before the slip clutch will release. By adjusting the strength of the adjustment spring, the slip clutch can properly load the torsion spring.
In a second embodiment of the bag tensioning assembly, the torsion spring bias member has a first end coupled to the support shaft and a second end coupled to the fixed support stand. The support shaft includes a friction block that contacts the core of the supply roll. A friction collar is installed on the opposite, outer end of the support shaft and includes a tension spring positioned between the collar and the core of the supply roll. The tension spring exerts a bias force to press the core against the friction block. As the support shaft rotates when the continuous strip of bags are withdrawn from the supply roll, the friction block slips relative to the core when the tension force of the torsion spring exceeds the friction force between the friction block and the core of the supply roll to maintain the desired load on the torsion spring. By adjusting the compression of the tension spring, the amount of tension force stored by the tension spring before slippage between the friction block and the core occurs can be adjusted.
The packaging apparatus further includes a printer assembly that is pivotable between a loading position and a printing position. In the printing position, the print head of the printer assembly is positioned adjacent to the platen roller of the bag feeding assembly. When a bag is to be printed by the printer assembly, a printer drive motor causes the print head to move downward into contact with the platen roller. The platen roller is driven to advance the printer ribbon through the printer assembly at the same speed as the speed of movement of the continuous strip of bags. Thus, the bag feeding assembly insures that the printer ribbon is advanced at the same speed as the continuous strip of bags.
The printer assembly can be released and pivoted away from the bag feeding assembly to the loading position. In the loading position, the continuous strip of bags from the supply roll can be quickly and easily fed through the packaging apparatus of the invention. Further, the positioning of both the drive roller and the platen roller of the bag tensioning assembly on the stationary support frame allows for quick, easy loading without threading the continuous strip of bags through multiple rollers.
As discussed above, the packaging apparatus of the present invention is capable of printing and loading each pre-opened bag during the operation of the packaging apparatus. The packaging apparatus positions the driven platen roller on the stationary support frame while allowing the printer assembly to move out of contact with the bag feeding assembly.
Various other features, objects and advantages of the invention will be made apparent from the following description taken together with the drawings.