The present invention relates to sealing a flexible container such as a plastic or paper bag used to package bread or the like. In particular, but not exclusively, the present invention relates to a sealing tape for closing an open end of a flexible container, such as a bag, and to a method of manufacturing such a sealing tape.

It is known to package food product, such as bread, in a paper or plastic bag and to close/seal an open end of the bag with a sealing tape. A bagging machine for packaging product in a bag typically includes a bag sealer, such as the FlexiPlus™ bag sealer from Select Bag Sealers Limited, which is an automatic bag sealer suitable for horizontal bagging applications. The bag sealer receives the neck of a bag being transported by a conveyor, applies a predetermined length of adhesive tape around the bag neck to close/seal the bag, and cuts the adhered ends of the tape, before repeating the sealing operation for another bag.

The bag sealer uses an adhesive tape that has equally pitched portions along its length where the adhesive has been neutralised and is configured to perpendicularly cut the tape in the middle of these neutralised portions in an attempt to provide a sealing tape having non-bonded ends which are easier to pull apart and open.

However, the non-bonded ends of a conventional sealing tape are still undesirably fiddly and frustrating to pull apart, particularly for children whose dexterity may not have fully developed or for the elderly and less able whose dexterity, eyesight and/or health may be compromised.

It is an aim of certain embodiments of the present invention to provide a sealing tape which is easier to open than a conventional sealing tape.

According to a first aspect of the present invention there is provided a method of sealing a bag, comprising:

locating an adhesive portion of an elongate piece of sealing tape around a neck of a bag; and engaging first and second non-adhesive end portions of the sealing tape together, wherein at least one of the non-adhesive end portions comprises an end edge region angled greater or less than 90 degrees with respect to a longitudinal axis of the tape.

Optionally, the end edge region is angled between around 30 and 80 degrees with respect to the longitudinal axis of the tape.

Optionally, both end edge regions are angled with respect to the longitudinal axis of the tape.

Optionally, both end edge regions define the same angle with respect to the longitudinal axis of the tape when the tape is in a planar state.

Optionally, the method comprises locating the adhesive portion of the tape in a transport path of the neck of the bag.

Optionally, the method comprises:

clamping at least one end portion of the tape with a first clamp; and moving the first clamp to apply a tension in the tape and pull the same across the transport path.

Optionally, the method comprises cutting the tape to provide at least the second end edge region.

Optionally, cutting provides the first end edge region of a further piece of sealing tape for sealing a subsequent bag.

Optionally, the method comprises urging the neck of the bag and tape through a pair of rollers to bring the non-adhesive end portions of the tape together and close the neck of the bag. According to a second aspect of the present invention there is provided apparatus configured to perform the method according to the first aspect of the present invention.

According to a third aspect of the present invention there is provided apparatus for sealing a bag, comprising:

a conveyor for moving a neck of a bag along a transport path;

a locator for locating a piece of elongate sealing tape around the neck of the bag, wherein the tape comprises an adhesive portion and first and second non adhesive end portions; and

a cutter configured to provide at least one of the non-adhesive end portions with an end edge region angled greater or less than 90 degrees with respect to a longitudinal axis of the tape.

Optionally, a cutting plane of the cutter is orientated at a cutting angle relative to the longitudinal axis of the tape which is less than or greater than 90 degrees.

Optionally, the cutter is selectively adjustable to set the cutting plane at a desired cutting angle.

Optionally, the cutting angle is between around 30 and 80 degrees.

Optionally, the apparatus comprises a first clamp configured to locate the tape across the transport path and apply a tension in the tape.

According to a fourth aspect of the present invention there is provided a sealing tape for sealing a bag, comprising:

a central adhesive portion located between first and second non-adhesive end portions, wherein at least one of the end portions comprises an end edge region angled greater or less than 90 degrees with respect to a longitudinal axis of the tape.

Optionally, both end portions have an end edge region angled greater or less than 90 degrees with respect to a longitudinal axis of the tape. Optionally, both end edge regions are orientated in the same direction.

Optionally, both end edge regions are orientated at substantially the same angle with respect to the longitudinal axis of the tape.

Optionally, the at least one end edge region is angled between around 30 to 80 degrees with respect to the longitudinal axis of the tape.

According to a fifth aspect of the present invention there is provided use of a sealing tape according to the fourth aspect of the present invention to seal a bag.

According to a sixth aspect of the present invention there is provided a bag comprising a sealing tape according to the fifth aspect of the present invention.

Description of the Drawings

Certain embodiments of the present invention will now be described with reference to the accompanying drawings in which:

Figure 1 illustrates apparatus for applying a sealing tape to the neck of a bag;

Figure 2a illustrates the tape transport path of the apparatus of Figure 1 ;

Figure 2b illustrates the sealing section of the apparatus of Figures 1 and 2a;

Figure 3a illustrates a cut portion of sealing tape according to certain embodiments of the present invention in a non-sealed state; and

Figure 3b illustrates the portion of sealing tape of Figure 1 in a sealed state when located around the neck of a bag or the like. Detailed Description

As illustrated in Figure 1 , a bag sealer 100 includes an input region 102 where a product-containing, open-ended, plastic or paper bag enters the sealer, and an output region 104 where a sealed bag leaves the sealer. The bag sealer 100 includes a conveyor in the form of driven belts and rollers to move a bag through the bag sealer from the input region to the output region in a direction illustrated by the arrows.

As illustrated in Figure 2a, the bag sealer 100 includes one or more user interfaces 206, such as a display/touchscreen, to allow an operator to selectively control and/or monitor the bag sealing process and/or a printing process. A reel of sealing tape 300 is rotatably mounted to the bag sealer and is fed through an optional printer 208, such as a thermal transfer type printer, by a plurality of rollers before entering the sealing section 250.

As illustrated in Figure 2b, the sealing section 250 includes a pair of opposed tape rollers 252,254 located adjacent to and upstream of a cutter assembly 256 for cutting the tape 300. The cutter assembly 256 comprises a pair of opposed knife elements 258,260 defining a cutting plane. Alternatively, the cutting assembly may comprise at least one cutting element operable in a linear manner by a linear actuator, such as a solenoid, or the like. The cutting plane of a conventional bag sealer is horizontal and perpendicular to the axis of the tape, whereas the cutting plane according to certain embodiments of the present invention is not perpendicular to the axis of the tape to thereby provide an angled cut, as described further below.

The sealing section 250 further includes a gripper 262 for gripping and applying a tension to the tape 300 to pull the same by a cut end region across the transport path of a bag to be sealed, and also a pusher 264 for receiving and urging the neck of a bag through the sealing section 250. The transport path through the sealing section 250 is defined by upper and lower rails 266,268 between which the bag neck is transported. A set of leaf springs 270 each mounted to a respective one of the rails defines a first restriction point and a set of rollers 272 each mounted to a respective one of the rails defines a second restriction point located downstream of the first restriction point. The restriction points act to restrict movement of the bag neck along the transport path, as described further below.

In use, a packed bag is transported towards the sealing section by a conveyor with a shelf to support and guide the open bag neck. The bag neck passes through at least one set of tensioning brushes that pull the neck out to tighten the bag around the product. As the neck of the bag leaves the brushes it is picked up between two continuously moving feed belts. These transport the bag neck through the bag sealer between the two pneumatically-loaded rails 266,268. The conveyor continues to move the main body of the packed bag through the bag sealer.

As the neck of the bag enters the feed belts, it triggers a sensor, such as a proximity switch. A corresponding signal is held by the controller until the bag neck passes and releases the product detector at which time the input signal to the controller is processed for the sealing sequence to start.

The rails 266,268 are pneumatically operated towards each other to define the first and second restriction points. The pusher 264 which is moving slightly faster than the belts and the conveyor, rises behind the bag neck and pushes the bag neck into a set of leaf springs 270 that prevent the bag making premature contact with the tape 300 which is held in tension across the transport path by the gripper 262. The leaf springs 270 which define the first restriction point along the transport path aid in providing a neat and tight seal around the bag neck. This is optionally further assisted by a bag clamp that holds down the outer end of the bag neck.

At the end of the previous sealing cycle, a length of the adhesive tape 300 with a non-adhesive portion at each end has been pulled down across the path of the oncoming bag neck between the two restriction points by the gripper 262. The tape 300 is cut by the cutter assembly 256 and held by a tape clamp coupled to the top rail 266 as well as still being held by the gripper 262 that initially pulled it down. The tape is cut substantially midway across the non-adhesive portion and an optical detector determines a location of the non-adhesive portion prior to cutting. The non adhesive portions are aptly coloured for efficient detection, e.g. black or red, and aptly contrast against a different colour, e.g. white or yellow, of the main adhesive portion. Non-adhesive end portions of a different colour to the central adhesive portion may also provide a visual indication to a user before gripping and pulling apart the end portions of a bag seal according to certain embodiments of the present invention to open a closed bag.

The pusher 264 forces the bag neck through the first restriction point defined by the leaf springs 270, or the like, against the adhesive tape 300 so that the tape adheres to the bag neck. At this time, the tape clamp opens to release the tape at its upper end region and the gripper 262 releases the tape at it lower end region. The pusher 264 forces the neck through the rollers 276 defining the second restriction point to bring the end portions of the tape together and form the seal around the neck of the bag. The bag clamp releases the outer end of the bag neck and the conveyor continues to move away the sealed bag.

The pusher 264 retracts and returns to the start position. The gripper 262 rises and the jaws thereof grip the free end of the adhesive tape 300 hanging between the knives of the cutter assembly 256. The gripper jaws close and the gripper lowers pulling the adhesive tape between the two restriction points ready for the next seal. The distance that the tape is pulled down each time is controlled by sensing the position of the non-adhesive coloured portions on the tape using a tape registration contrast scanner, and then applying a fixed (+/- 1 5mm) compensation to the stroke to rectify any errors, if required.

According to certain embodiments of the present invention, the cutter assembly 256 is selectively orientated such that its cutting plane and thereby a cut made across the tape 300 is not perpendicular to the axis of the tape, i.e. the cutting plane is orientated at a cutting angle relative to a longitudinal axis of the tape which is less than or greater than 90 degrees. Aptly, the cutter assembly 256 may be fixed at a predetermined angle by securing the cutter assembly at the required angle to the frame of the bag sealer using pre-drilled threaded holes and bolts for example.

Alternatively, the cutting assembly 256 may be selectively adjustable by securing the same to a frame/body of the bag sealer via at least one slotted aperture in the form of a segment of a circle to allow the cutter mechanism to be rotated across a range of angles, the securing bolt/s being tightened when a desired alignment/predetermined cutting angle is correct. An engraved indication or the like of the angle may be provided on a rotatable chassis of the cutting assembly. The range of angle is aptly between around 30 to 90 degrees, wherein 90 degrees is perpendicular to the longitudinal axis of the tape to allow the cutter assembly to be used for producing conventional bag seals as well. The preferred angle in accordance with certain embodiments of the present invention is around 75 degrees with respect to the longitudinal axis of the tape, i.e. around 15 degrees with respect to a lateral axis of the tape. An edge angle of around 10-30, and preferably around 15-20 degrees, with respect to the lateral axis of the tape has been found to be an optimal angle to provide a sufficient edge length for a user to efficiently engage with a finger and move/lift away from the opposed tape end region to peel open the tape, whilst presenting a suitable non-overlapping area of each non-adhesive end region to act as a visual guide to urge the user to open the tape by moving the end regions apart.

As illustrated in Figure 3a, a sealing tape 300 according to certain embodiments of the present invention includes an adhesive disposed on a first surface thereof and equally spaced non-adhesive portions 304 where no adhesive has been applied to the tape or where the applied adhesive has been neutralised.

The tape is around 12mm wide and has a thickness (gauge) of at least around 40pm. The main adhesive-carrying portion 302 is around 90-1 10mm long, i.e. the non-adhesive portions 304 are axially spaced by around 85-120mm and aptly around 90-1 10mm depending on the application for the sealing tape. For example, a spacing of around 1 10mm is desirable for relatively stiff bags, such as paper bags. The tolerance for positioning of the non-adhesive portions is around +/- 0.5mm. The non-adhesive portions 304 are aptly around 20-30mm long and preferably around 25mm +/- 1 mm. However, other tape dimensions, tolerances and materials can used for a particular application. For example, the tape substrate may be a plastics or paper material, such as Polypropylene or sometimes PVC, and the adhesive may be a rubber or acrylic-based adhesive for example. Aptly, the adhesive has a relatively high tack and high initial grab and also is resealable with a relatively low tendency to leave residue behind when the tape ends are pulled apart. As described above, in accordance with certain embodiments of the present invention, the tape 300 is cut during the sealing process at a predetermined angle with respect to a longitudinal axis of the tape, wherein the angle is not perpendicular to the tape axis. As illustrated in Figure 3a, a cut is made substantially in the middle of each non-adhesive portion such that each piece of tape to be located around the neck of a bag passing through the sealer 100 comprises a central adhesive portion 306 and a pair of non-adhesive end portions 308,309 each having a respective angled end edge 310,31 1 . The end edges are angled in the same direction relative to the tape axis and define the same angle with respect to the longitudinal axis of the tape.

When the piece of tape is urged around the bag neck, the central adhesive portion 306 adheres to the bag neck and also to itself, and the non-adhesive end portions 308,309 engage each other but do not adhere to each other in the absence of adhesive.

As illustrated in Figure 3b, the angled end edges 310,31 1 of each end portion 308,309 are oriented in opposed directions when the piece of tape 400 is located around the neck of a bag and effectively folded over on itself. The angled end edges 310,31 1 result in an end of each end portion extending beyond the end edge of the other end portion thereby defining a pair of‘ears’. Each ear provides a handle element 410,412 to allow a user to efficiently locate and hold each end portion of the tape seal and effectively pull apart the end portions of the tape to open the sealed bag.

The angle of cut is aptly around 60 degrees with respect to a longitudinal axis of the tape or around 30 degrees with respect to a transverse axis across the tape.

However, the angle of cut may be varied to suit a particular application.

Furthermore, the angled end edges 310 of the non-adhesive portions 308,309 may be substantially straight as illustrated or may be at least a portion of the cut may be substantially curved, e.g. to eliminate any points, subject of course to the form of cutting device, e.g. a pair of opposed knives may form a straight cut across the tape whereas a stamping process or the like may be required to form a curved cut across the tape. Further alternatively, an angle of one of the end edges may be different to the other end edge. For example, one end edge may be substantially transverse, i.e. perpendicular to the tape axis, whereas the other end edge may be angled to the perpendicular, i.e. at an angle greater or less than 90 degrees, such that at least a portion of the angled end portion extends beyond the transverse end portion, or vice versa, to provide at least one handle element for efficiently locating and separating the end portions. As another example, one non-adhesive end portion may have a substantially transversely cut end edge, whereas the other end portion may have an end edge which is angled from the transverse axis and is substantially symmetrical with respect to the tape axis, e.g. a triangular or semi-circular end edge. A first end portion having a symmetrical and angled first end edge engaged with a second end portion having a transverse end edge and a larger surface area thereby provides two handle elements for a user to choose from to locate and pull the second end portion away from the first end portion.

In a preferred embodiment, each non-adhesive portion extends a distance along the tape from the angled cut, as illustrated by the interface line 420 between the non adhesive end portions 308,309 and the adhesive portion 306. However, the non adhesive portion may stop at the angled cut such that the imaginary interface line extends perpendicularly across the tape from the edge of the tape where the angled cut starts, i.e. the non-adhesive portion may be substantially triangular and not include a substantially rectangular portion.

Certain embodiments of the present invention therefore provide a method of sealing a bag for containing a foodstuff which allows a user, such as a child or elderly person, to easily locate the ends of the sealing tape otherwise closing the bag and effectively pull the ends apart to open the bag. Pre-cut pieces of sealing tape may be provided for a particular application, e.g. for manual application to a bag neck, wherein each piece of tape includes a central adhesive portion and first and second non-adhesive end portions each having an end edge which is oriented by more or less than 90 degrees with respect to a longitudinal axis of the tape. A sealing tape for use in a bag sealing machine may also be provided, wherein the sealing tape comprises a plurality of joined tape pieces, e.g. by frangible regions, and each piece of tape includes a central adhesive portion and first and second non-adhesive end portions each having an end edge which is oriented by more or less than 90 degrees with respect to a longitudinal axis of the tape. A bag sealer configured to locate a piece of sealing tape around the neck of a bag according to certain embodiments of the present invention is also provided, such as a floor-mounted bag sealing machine wherein a neck of a bag is conveyed along a transport path towards a tape applicator and cutter by a mechanical conveyor or a counter-top apparatus wherein the neck of a bag is conveyed along a transport path by a user, such as a butcher or baker.