IES61015B2 - A carton manufacturing process - Google Patents

Description

A carton manufacturing process This invention relates to a process for manufacturing a cardboard packaging carton, and in particular wherein a selected number of different types of cartons are being repeatedly produced in relatively small batches.

According to the invention there is provided a process for manufacturing cardboard packaging cartons comprising the steps:delivering a number of sets of printing plates to a printing station; mounting a set of printing plates on a printing machine at the printing station; passing one or more cardboard test sheets through the printing machine, inspecting each sheet and adjusting the printing machine if necessary to correctly register indicia printed on each sheet; passing a number of blank cardboard sheets through the printing machine, printing a pattern of indicia associated with a number of carton blanks on an exterior surface of each sheet and subsequently applying varnish to said exterior surface of the sheet; stacking the printed sheets and delivering the stacked sheets to a stamping station; mounting a stamping die carried by an associated metal chase in a stamping machine at the stamping station, the stamping die comprising a wooden panel having a number of metal cutting and creasing blades Γ» S ·Ί Π < Γ) - 2 extending outwardly of a front surface of the panel, the die being rigidly mounted in the associated metal » chase, bringing the cutting and creasing blades of the die into alignment with associated printed cardboard sheets delivered through the stamping machine; passing the printed sheets through the stamping machine, cutting and scoring each sheet, defining on each sheet a number of flat carton blanks with fold lines for each blank; delivering the stamped sheets to a stripping station; passing each stamped sheet through a stripping machine at the stripping station, removing waste material from an interior portion of each stamped sheet; discharging each sheet from the stripping machine and removing waste material from a periphery of each sheet to leave a number of carton blanks; and delivering the carton blanks for packaging or optionally delivering the carton blanks through a folding and gluing station for forming a carton from each blank prior to packaging.

In one embodiment of the invention varnishing of the printed sheet is carried out in two stages by passing each printed sheet through a first set of varnish rollers for applying a coat of a low-slip varnish to selected areas of a printed face of the sheet and then passing the sheet lz through a second set of varnish rollers for applying a coat of a high-slip varnish to the remaining unvarnished area of the printed face of th© sheet. Ideally a boundary of the coat of low-slip varnish is defined along fold and/or cut lines of the sheet.

In another embodiment the process includes the step of returning waste cardboard sheets rejected during the process to the printing station for subsequent re-use of the waste sheets as the test sheets.

In a further embodiment the process includes the step of retaining a number of selected stamping dies each mounted in an associated chase at the stamping station in a chase storage housing having a. number of slots each for reception of a chase, supporting each chase vertically within its associated slot, the chase engagable with spacers within the slot to support the die spaced-apart from side walls of the slot.

In another embodiment the process further includes the steps of: mounting a stack of carton blanks on a ram operated elevator adjacent and spaced-apart from an inlet of a folding and gluing machine at the folding and gluing station; taking each carton blank from the stack and feeding the carton blank into an inlet of the gluing and folding machine; controlling the vertical position of the elevator by operating the ram to facilitate transfer of blanks from the elevator to the gluing and folding machine; delivering each carton blank through the folding and gluing machine; formed „ 4 _ folding each carton blank along previously crease lines; applying adhesive to peripheral portions of the carton blank which are glued together to form a carton; stacking a number of cartons in a flat collapsed position, and packaging the cartons.

In another embodiment the process includes the steps of: leading each carton blank along a feed conveyor to a labelling station at the gluing and folding machine; de-reeling a backing strip carrying peel-off adhesive labels from a supply reel; leading the backing strip around a peel-off roller adjacent the feed conveyor and spooling the backing strip onto a drivable spool; peeling a label away from the backing strip at the peel-off roller and adhering the label to a carton blank as it passes alongside the peel-off roller; delivering the carton blank past a label detector downstream of the labelling station to sense the presence of a label on the blank, rejecting any blanks not having a label attached thereto.

In another aspect the invention provides a carton or carton blank whenever produced according to the process as previous described.

In a further aspect the invention provides apparatus for carrying out the process as herein described.

The invention will be more clearly understood by the following description of some embodiments thereof, given by way of example only, with reference to the accompanying drawings f in which:~ Fig. 1 is a schematic flowchart illustrating a process for manufacturing cardboard packing cartons according to the invention; Fig. 2 is a perspective illustration of a die storage rack; Fig. 3 is a detail perspective view of portion of the die storage rack; Fig. 4 is a detail end view of portion of the die storage rack; Fig. 5 is a detail perspective view of a die panel; Fig. S is a detail perspective view showing portion of a chase support housing; Fig. 7 is a perspective view of an elevator used in the process; Fig. 8 is a plan view of a labelling station used in the process; and Fig. 9 is a perspective view of the labelling station.

Referring to the drawings, a process and apparatus for manufacturing cardboard packaging cartons will be described.

Sets of printing plates are delivered from a printing plate store 10 to a printing station 12, the plates being delivered to a plates in bin 14 adjacent a printing machine at the printing station 12. Advantageously, a number of sets of plates for a number of print runs are held ready for use in the bin 14. After a set of plates has been used on a print run, they are removed from the printing machine and stored in a plates out” bin 16 from which they are returned from the printing plate store 10. A desired set of printing plates is selected from the bin 14 and mounted on the printing machine which is set up for a print run. Conveniently, one or more waste cardboard sheets, that is sheets that have been rejected during previous processing, are used for setting up the printing machine on a test run. Thus advantageously new cardboard sheets need not be used in the set up and maximum use is made of waste material to minimise costs. Each test sheet printed is inspected and the printing machine adjusted if necessary to correctly register indicia printed on each sheet.

A stack of new blank cardboard sheets 20 is delivered from a sheet store 21 to an inlet of the printing machine. The new sheets are then passed through the printing machine printing indicia on an exterior surface of each sheet and then applying a varnish to said exterior surface. A repeat pattern of indicia associated with a number of carton blanks is printed on each sheet. Printed sheets are then stacked on pallets at an outlet of the printing machine for subsequent transport to a stamping station 25.

At the stamping station 25, each sheet has a number of carton blank shapes (corresponding to the sets of indicia) applied by a stamping die to the sheet to define a desired outline of each carton blank on the sheet together with intermediate fold lines and/or creases for each carton blank on the sheet.

Each stamping die 27 comprises a wooden panel 28 having a front surface 29 with a number of upstanding metal cutting and creasing blades (not shown) extending outwardly of the front surface 29. For storage, conveniently a pair of suspension pins 30 are mounted spaced-apart adjacent an upper edge of the panel 28. The pins 30 project outwardly at each side of the panel 28 and slidably engage associated tracks 32 on a support frame 33. Thus, the dyes 27 are readily easily and conveniently stored vertically suspended on the support frame 33 when not in use. For use, a dye 27 is mounted in an associated rectangular metal chase and then the chase is mounted in the stamping machine 25.

Due to the nature of wood, when the panels 28 are not mounted in a chase, some distortion of the panels will occur. While the distortion may be relatively small - in the order of 1-2 mm, this is enough to effect cutting and creasing of the sheets. Considerably time has therefore to be spent in correctly mounted and aligning each panel 28 in a chase and in correctly setting up the stamping machine. In addition to time loss, there is wastage due to imperfect sheet stamping at the stamping machine while it is being set up. Advantageously, according to the present invention, a number of commonly used stamping dies are retained in their chase ready for use adjacent the stamping machine 25 in a chase storage housing 70. Thus, the stamping dies which are used on often repeated small print runs are held ready for use. As each die is permanently mounted in a chase, unacceptable distortion does not occur and the chase can readily easily and quickly be mounted on the stamping machine and quickly set up ready for use. Make-readv time is thus minimised and V this is particularly advantageous where a relatively large number of small print runs are carried out and the stamping dies thus have to be regularly changed.

Fig. 6 shows the chase storage housing 70. The housing 70 has a base 71 with upstanding end walls 72 at each end of the base 71 and a number of intermediate dividing walls 73 defining therebetween a number of vertical slots 74 each for reception of a chase 75 carrying a stamping die 27Spacers 7o on the walls 72, 73 engage the chase 75 to keep the die 27 clear of the walls 72, 73 for protection of the die 27. It will be noted that each wall 72, 73 has a tapered front edge 77 to allow the dies 27 be viewed for selection. A top panel 78 and back panel (not shown) span the walls 72, 73.

When the required chase is mounted in the stamping machine 25 and properly set up, the printed sheets are delivered through the stamping machine 25 defining on each sheet a number of flat carton blanks of a desired shape.

The sheets which have been cut and creased are delivered to a stripping station 39 where the waste material surrounding the defined carton blanks is stripped away. This stripping may be carried, out by a stripping machine. Preferably, however, according to the invention, the stripping machine is merely set up to remove the waste from an internal portion of each sheet and the waste at a periphery of each sheet is subsequently manually stripped away. Thus advantageously, the make-ready time for stripping machine is minimised when it is being set up prior to delivering sheets for a particular print run through the stripping machine. Again, this is particularly advantageous where a relatively large number of small print runs are being carried out. When stripping has been completed, the carton blanks are stacked in bundles.

The carton blanks thus formed may then be packaged at a packing station 40. Alternatively, the carton blanks may be delivered to a gluing station 41.

At the gluing station, a pallet of stacked carton blanks is mounted on an elevator 42 (Fig. 7) at an inlet of a folding and gluing machine. The elevator 42 has a platform 43 on which the pallet is mounted. This platform 43 is carried on a scissors linkage 44 operated by means of an associated ram 45. Advantageously, the elevator 42 is mounted in a shallow pit 47 in the ground. The platform 43 is vertically movable by means of the ram 45 between a retracted stored position within the pit 47 in which a top surface of the platform 43 is flush with the ground and a raised position as shown in the drawing. Thus the platform 43 can be safely retracted into the pit 47 when not in use and for loading. During use, an operator can raise the platform 43 for feeding carton blanks from the platform 43 into the folding and gluing machine. Advantageously, the operator does not have to bend down to pick up carton blanks from the platform 43 with consequent risk of back injury, and further the feed of carton blanks to the folding and gluing machine can be carried out more quickly. At the gluing station 41, each carton blank is folded along previously formed crease lines and adhesive is applied to peripheral portions of the carton blank which are glued together to form the carton. The cartons are then stacked flat in a collapsed position and packaged at a packing station 49.

Advantageously, during the folding and gluing process, one or more labels may be applied to each carton blank. Figs. 8 and 9 show a labelling station 50 which can be selectively operated during the folding and gluing of each carton blank 51. The labelling station 50 is mounted alongside a feed conveyor 53 delivering a number of carton blanks 51 through the folding and gluing machine. A reel 54 of labels is rotatably mounted on a rotatable support post 55. A backing strip 56 carrying a number of peel-off labels 57 is lead around a peel-off roller 58 and attached to a drivable spool 59. By driving the spool 59, the backing strip 56 is reeled from the roller 55 onto the spool 59 around the roller 58. As the backing strip 56 passes around the roller 58 a leading edge of each label 57 parts from the backing strip 56 and adheres to an adjacent flap 62 on each carton blank 51 as it passes along the conveyor 53 beside the roller 58. The flap 62 passes between a guide arm (not shown.) and the roller 58 for reception of the label. Downstream of the labelling station 15 a photoelectric label detector (not shown) is provided to check that a label is applied to each carton blank 51. The detector may be operatively connected to the drive of the conveyor 53 to stop the conveyor 53 if an unlabelled carton blank 51 is detected.

In some cases, it is desired to apply a foil to an exterior of the carton after printing. In this case, a low-slip (low silicone) varnish must be used and the foil will not securely adhere to a high-slip varnish. However, for feeding the blanks through automated machinery preferably a high-slip varnish should be used otherwise the blanks can jam in the machinery causing delays, wastage and possibly damage to the machinery. To overcome this problem, advantageously according to the invention, two separate coats of varnish are applied to each blank at the printing station. A first coat of low-slip varnish is applied by a first set of varnish rollers to areas of the printed sheet to which foil is to be attached. The remaining area is then coated with a high-slip varnish by delivering the sheet through a second set of varnish rollers. Ideally the boundary between the two varnished areas is formed along fold and/or cut lines so that the differences in the varnishes used is less noticeable.

A carton blank feeder may be provided for feeding carton blanks into a gluing and folding machine. The feeder typically comprises an endless chain having a number of upstanding arms which engage and feed carton blanks from an inlet into the gluing and folding machine. The feeder is designed to feed carton blanks at a speed of 8,000 units per hour. Advantageously, however, the throughput of the feeder may be increased by 50% to 1200 units per hour for smaller carton blanks (less than 12 x 8). To do this, the drive gear for the chain is changed to increase the speed and the spacing of the upstanding arms on the chain is narrowed with additional pick-up arms being added where necessary.

The invention is not limited to the embodiments hereinbefore described which may be varied in both construction and detail.

Claims (5)

1. A process for manufacturing cardboard packaging cartons comprising the stepssdelivering a number of sets of printing plates to a printing station; mounting a set of printing plates on a printing machine at the printing station; passing one or more cardboard test sheets through the printing machine, inspecting each sheet and adjusting the printing machine if necessary to correctly register indicia printed on each sheet; passing a number of blank cardboard sheets through the printing machine, printing a pattern of indicia associated with a number of carton blanks on an exterior surface of each sheet and subsequently applying varnish to said exterior surface of the sheet; stacking the printed sheets and delivering the stacked sheets to a stamping station; mounting a stamping die carried by an associated metal chase in a stamping machine at the stamping station, the stamping die comprising a wooden panel having a number of metal cutting and creasing blades extending outwardly of a front surface of the panel, the die being rigidly mounted in the associated metal chase, bringing the cutting and creasing blades of the die into alignment with associated printed cardboard sheets delivered through the stamping machine; passing the printed sheets through the stamping machine, cutting and scoring each sheet, defining on each sheet a number of flat carton blanks with fold lines for each blank; delivering the stamped sheets to a stripping station; passing each stamped sheet through a stripping machine at the stripping station, removing waste material from an interior portion of each stamped sheet; discharging each sheet from the stripping machine and removing waste material from a periphery of each sheet to leave a number of carton blanks; and delivering the carton blanks for packaging or optionally delivering the carton blanks through a folding and gluing station for forming a carton from each blank prior to packaging.

2. A process as claimed in claim 1 wherein varnishing, of the printed sheet is carried out in two stages by passing each printed sheet through a first set of varnish rollers for applying a coat of a low-slip varnish to selected areas of a printed face of the sheet and then passing the sheet through a second set of varnish rollers for applying a coat of a high-slip varnish to the remaining unvarnished area of the printed face of the sheet; and preferably including the step of returning waste cardboard sheets rejected during the process to the printing station for subsequent re-use of the waste sheets as the test sheets; and preferably including the step of retaining a number of selected stamping dies each mounted in an associated chase at the stamping station in a chase storage housing having a number of slots each for reception of a chase, supporting each chase vertically within its associated slot, the chase engagable with spacers within the slot to support the die spaced-apart from side walls of the slot.

3. A process as claimed in any preceding claim wherein the process further includes the steps of: mounting a stack of carton blanks on a ram operated elevator adjacent and spaced-apart from an inlet of a folding and gluing machine at the folding and gluing station; taking each carton blank from the stack and feeding the carton blank into an inlet of the gluing and folding machine; controlling the vertical position of the elevator by operating the ram to facilitate transfer of blanks from the elevator to the gluing and folding machine; delivering each carton blank through the folding and gluing machine; folding each carton blank along previously formed crease lines; applying adhesive to peripheral portions of the carton blank which are glued together to form a carton; stacking a number of cartons in a flat collapsed position, and packaging the cartons; an optionally leading each carton blank along a feed conveyor to a labelling station at the gluing and folding machine; de-reeling a backing strip carrying peel-off adhesive labels from a supply reel; leading the backing strip around a peel-off roller adjacent the feed conveyor and spooling the backing strip onto a drivable spool; peeling a label away from the backing strip at the peel-off roller and adhering the label to a carton blank as it passes alongside the peel-off roller; delivering the carton blank past a label detector downstream of the labelling station to sense the presence of a label on the blank, rejecting any blanks not having a label attached thereto.

4. A process substantially as hereinbefore described with reference to the accompanying drawings.

5. A carton or carton blank whenever produced according to the process as claimed in any preceding claim.