GB2367262A

GB2367262A - Method and apparatus for producing packaging blanks

Info

Publication number: GB2367262A
Application number: GB0122796A
Authority: GB
Inventors: Nigel Richard Mawditt
Original assignee: IND AUTOMATION SYSTEMS Ltd
Current assignee: IND AUTOMATION SYSTEMS Ltd
Priority date: 2000-09-21
Filing date: 2000-09-21
Publication date: 2002-04-03
Anticipated expiration: 2020-09-21
Also published as: GB2367262A8; GB2367262B; GB0023156D0; GB0122796D0

Abstract

Apparatus for producing packaging blanks from a continuous strip (20) of material having images printed at intervals therealong is disclosed. At least one set of perforations (9a) are formed in the strip (20) parallel to its length by a rotary perforator (29;50) and a section of the strip (20) is separated from the remainder thereof by a separator cutter (37;54) to form a blank (12;40), in which periodic adjustments to the relative position of the strip (20) and the separator cutter (37;54) are made to maintain the registration of the images in relation to the separation line made by the said separator cutter without disengaging the perforator (29;50) from the strip (20). A method of producing packaging blanks (12;40) is also disclosed and the invention comprehends also a blank made by this method and a package.

Description

METHOD AND APPARATUS FOR PRODUCING PACKAGING BLANKS

The present invention relates to a method and apparatus for producing packaging blanks, and especially but not exclusively, for the production of packaging blanks for a flip top pocket such as a cigarette packet.

In fact, cigarettes are not the only commodities or products supplied to the consumer in flip-top packets or cartons and it is to be understood that reference herein to the application of the invention to cigarette packets is without prejudice to the generality thereof. Such packets or cartons generally have a top portion attached to the rest of the packet along one fold or hinge line about which the top portion can be turned back to expose the contents. Within the opening thus formed is held an insert, known as the"inner frame"against which the top engages by friction upon closure.

Such packets are generally made from a first blank which is folded to form the entire packet including the flip top, and the inner frame is made from a second, separate blank which is attached by adhesive to the inner surface of the packet. The inner frame fits into the opening in the packet and in order to provide a secure frictional engagement with the top is provided with small laterally extending tabs which engage with the flip-top when it is closed. Such tabs are formed by shaped elongate slots or incisions in the blank from which the inner frame is formed. Aligned with such slots or incisions are respective fold lines each defined by a line of weakening formed by a row of perforations extending parallel to the slot and on either side thereof. Blanks for such inner frames are made from a continuous elongate strip of material, typically

board, from which individual blanks are cut by a shaped separator cutter to which the strip is fed in steps. The perforations, including the elongate slots or incision are formed continuously along the length of the strip by a rotary perforator positioned just upstream of the separator cutter with respect to the direction of advance of the strip towards the separator.

In known package-making machines the movement of the various parts of the machine are synchronised, typically by a mechanical arrangement such as a geneva wheel so that the position of the incision or slot is correctly located with respect to the edge of the blank when this is cut off from the strip by the separator.

Although this system works satisfactorily it has certain limitations and imposes certain constraints on the formation of the inner frame. For example, because of the need for perforations longitudinally of the strip to form the fold lines for the sides of the inner frame there has to be a fixed relationship between the rotary perforation and the separator cutter otherwise the tabs formed by the shaped elongate slot or incision on bending along the fold lines defined by the perforation would not be in the correct position for retaining the flip top when it is closed. This has in the past precluded the printing of any images or other printable material (e. g. text) on the inner frame due to the fact that printing on a separate printing machine would result in different tolerances and variations which would result in the print being out of register with the outline of the blank over at least part of the length of the strip. Although the relationship between the strip and the cutter could be adjusted by varying the speed of advance of the strip this cannot be achieved in the prior art due to the permanent

engagement of the perforator which itself must maintain a fixed relationship with respect to the separator.

The present invention seeks to provide apparatus and a method by which this can be achieved without compromising the fixed relationships which must be maintained.

According to the present invention, therefore, there is provided apparatus for producing packaging blanks from a continuous strip of material having images printed at intervals therealong, in which at least one set of perforations are formed in the strip parallel to the length of the strip by a rotary perforator prior to separation of a section thereof by a separator cutter to form a blank, in which periodic adjustments to the relative position of the strip and the separator cutter are made to maintain the registration of the images in relation to the separation line made by the said separator cutter without disengaging the perforator from the strip.

The registration adjustments to the relative positions of the separator cutter and the strip may be achieved in one of two ways, that is by moving the separator cutter parallel to the length of the strip in one direction or the other to accommodate differences in registration, or by accelerating or decelarating the strip with respect to the perforator while the elongate blade cutting the slot or incision is in contact with the strip. Obviously, since the perforations are short and separated by short"bridges" of material, relative adjustment between the perforator and the strip cannot be undertaken when the perforator cutters are engaged with the strip since this could result in shortening and thus weakening of the bridges effectively resulting in the

formation of a single elongate incision in place of the perforations.

Thus, in apparatus for producing packaging blanks in which the perforator has a plurality of shorter blades for producing short perforations and at least one longer blade for producing an elongate perforation, the adjustments to the relative position of the strip and the perforator may be made when the said longer blade is engaged with the strip.

An elongation or shortening of the incision by an amount sufficient to effect adjustment for registration purposes will, within limits, not materially affect the function of the tabs produced by the incision, and relative movement between the strip and the perforator can take place without damage as the incision created by the long blade, although adding a certain amount of additional resistance to the adjustment movement of the strip, can be achieved by appropriate displacement of the strip itself.

In fact, for this purpose, it is preferred that drive means (such as nip rollers) are provided on either side of the perforator in order to drive the strip and, in particular, to make the adjustment movement.

Such drive rollers, called hereinafter transport rollers, determine the transport speed of the strip and these may themselves be driven by respective independent motors, in particular electric motors, although air motors may also be used in some circumstances.

In its broadest aspect, therefore, the apparatus has means for varying the registration

adjustment by varying the relative positions of the strip and the separator cutter. This could, of course, be achieved by varying the phase of the separator cutter as well as, or instead of varying the position of the strip by displacing it with respect to its normal movement, either by advancement or retardation.

If the separator cutter is adjusted in order to make the necessary changes it is preferable for this to be returned to a reference position after separating a blank from the strip. This is of particular importance if a reciprocating blade (rather than a rotary blade) is used for the separator cutter as continual adjustment in one direction may be limited by the potential range of movement of the separator cutter.

It is preferable for the adjustment movements to be made as a relative advancing movement of the strip in relation to the separator cutter or a displacement in the advancement direction of the strip of the separator cutter. Thus, if the strip requires to be retarded in order to effect registration, this is achieved by advancing the separator cutter and then returning it to its reference position for a subsequent cut, whereas if the registration adjustment requires advancement of the strip this can be achieved by changing the phase of the drive motors by which the transport rollers are driven.

Such phase adjustment for registration may be effected by accelerating the motors (whether electric or air motors) driving the strip transport rollers with respect to the motor driving the rotary perforator. In this configuration the rotary perforator acts as the fixed frame of reference with respect to which the separator cutter and the

transport rollers, being the other two of three variables in the system, are adjustable.

It would, of course, be possible to select another of the two variables to be effectively fixed, and adjust the position (that is the phase) of the other two in order to effect registration adjustments.

As mentioned above there are conventionally provided transport rollers on either side of the perforator roller and, in addition, there may be further provided at least one pair of transport rollers in advance of the said strip transport rollers whereby to create an open loop in the strip between a reel thereof and the rotary perforator, whereby to ensure there is substantially no residual tension in the strip as it arrives at the strip transport rollers.

The electric drive motors may be stepped at a fixed duty cycle to match incremental advancing movements of a packaging machine of which the apparatus forms part.

The rotary perforator and the transport rollers may be all independently driven by the said electric motors.

The present invention also comprehends a method of producing printed blanks for a package from a continuous strip of material printed with images at intervals along its length, comprising the steps of perforating the strip parallel to its length with a rotary perforator, cutting the strip into blanks with a separator cutter, and periodically adjusting the relative longitudinal position of the strip and the separator cutter by causing relative displacement thereof while the perforator remains engaged.

The present invention also comprehends a packaging machine incorporating apparatus for varying the registration between preliminary printed images on a strip of material from which at least part of the package is to be formed and the cutting and perforating elements of the packaging machine.

The present invention also provides an improved process for the continuous production of blanks for forming an inner frame for a flip-top carton, which allows a portion of that inner frame to have a pre-printed design or image visible when the inside of the carton is exposed.

Prior art packaging machines are not able to carry out such a process, in particular as they are not able to maintain the print images in register with respect to the perforator and blank cutter. The apparatus of the present invention enables production of blanks for inner frames for flip-top cartons, which inner frames carry a pre-printed image or design.

According to a further aspect of the present invention there is provided apparatus for the continuous production of blanks capable of forming inner frames for flip-top cartons which inner frames when inserted into a carton have means for engaging the flip-top of the carton to retain it releasably in a closed position and a part of which is visible when the flip-top of the carton is open, which visible part carries a printed image, which apparatus comprises: means for conveying a continuous strip (typically card);

a perforator for forming perforations longitudinally of the strip ; a blank-cutting member for dividing the continuous strip into discrete blanks ; means for synchronising the perforator and the blank cutter; means of determining the position of one or more printed images on the strip being conveyed through the apparatus; means for adjusting the relative position of the strip bearing the printed image and the perforator; and means for adjusting the position of the blank-cutting member with respect to the position of the perforator.

The apparatus of the present invention thus may have a print registration system which includes means for detecting the position of images located at discrete positions on the strip. Any suitable detection means, such as a photodetector, may be used and this may be positioned at a convenient location along the path of the strip. It is especially convenient for the detector to be positioned downstream of the perforator between this and the blank cutter. It may detect the or a part of the image to be exposed in the open flip-top carton or it may detect a print registration mark provided at a precise location either on the printed strip from which the blank is to be formed or on a removable addition piece. Determination of the position of the print on the card may be carried out either periodically or continuously.

As mentioned above the perforator may also form the engagement tabs or a precursor of those engagement tabs; which only form into engagement tabs after folding the blank from which the inner frame is formed. Fold lines may be produced by providing

an indented line cut partially through the thickness of the strip as well as or instead of the perforation extending right through the thickness of the strip, which is usually card.

Adjustment of the position of the print on the card with respect to the engagement means forming member may be effected by any suitable means by which the relative positions can be varied. In some cases it may be advantageous to provide means for separating the strip or card from the perforator means or the roller on which it is carried. Such means may take the form of a cam roller positioned either upstream or downstream of the perforator means so as to be able to release the strip or card to allow independent movement of the strip or card and the perforator means to allow relative phase slighting before re-engagement.

The apparatus may utilise a pull-on-demand or driven feed system. The various transport and perforator rollers, and the adjustment means, may be independently and individually driven, for example by servo drives. Any separating means as mentioned above (for separating the card from the perforator may also be likewise independently and individually driven. A central control unit is preferably provided to control all of the components and to ensure correct synchronisation.

The apparatus may form part of a larger packaging machine or it may take the form of a module for addition to existing packaging machinery to replace the synchronism mechanism. The apparatus is particularly suitable for use in machinery for packaging a commodity such as cigarettes. In such machinery the blank for the inner frame is

first orientated with respect to a blank for an outer member of a carton and applied thereto either after or preferably before the blank is folded into the assembled carton.

The inner frame is orientated so that the image on its first part is exposed above an edge of the carton when open. The assembled carton is then orientated with respect to a commodity packing machine which fills the carton and then closes it and if required provides it with overwrapping packaging.

As mentioned above, for many conventional flip-top cartons, the flip-top is loosely retained in the closed position by means of two engagement tabs extending laterally out a small distance from the inner frame. Such engagement tabs are conventionally formed by the provision of an elongate slot provided in a fold line in the blank from which the inner frame is formed. Conventionally for each size of flip-top carton to be produced a differently sized elongate slot is required. For this reason in the past differently sized packets were manufactured on separate machines.

The present invention provides a process which allows differently sized flip-top cartons to be produced on the same machine. In particular a carton having a pierced front face to allow the contents to be seen through it may also be formed within the ambit of the invention.

According to another aspect of the present invention there is provided a process for the continuous production of blanks capable of forming inner frames for a variety of sizes of flip-top cartons, which inner frames when inserted into a carton have means of engaging the flip-top of the carton to retain it releasably in a closed position, which

process comprises the steps of : conveying a continuous piece of strip or card from a source to a first processing station; providing the card in the first processing station with engagement tabs by contacting the card with an engagement tab cutter member; conveying the card provided with the engagement tabs to a second processing station; dividing the continuous card in the second processing station into discrete blanks by means of a cutting member; and synchronising the engagement tab forming member and the cutting member of the first and second processing stations respectively, in which process the length of the engagement means made by the engagement tab forming member is varied by varying the amount of relative movement occurring between the card and the engagement tab forming member whilst they are in contact with each other.

In other embodiments of the invention the perforator and the separator may be carried on the same roller or drum. Because the perforators extend all the way around the roller or drum there is still a need for registration adjustments to be made without disengaging the perforator from the strip.

Various embodiments of the present invention will now be more particularly described, by way of example, with reference to the accompanying drawings, in which :

Figure 1 is a perspective view of a flip top a carton having an image in the flip frame ; Figure 2 is a plan view of a blank for forming the flip frame of the carton illustrated in Figure 1; Figure 3 is a schematic side view of one embodiment of apparatus according to the present invention; Figure 4 is a schematic perspective view of a detail alternative form of frame; Figure 5 is a perspective view of a carton having an opening in the front using the inner frame of Figure 4; Figure 6 is a perspective view of part of an alternative embodiment of the inventions; and Figure 7 is a partial perspective view of a further alternative embodiment of the invention.

A flip-top cigarette carton 1 is shown in Figure 1. The carton I is generally rectangular in shape and has an outer case 2 having opposing pairs of sides which with the bottom of the outer case 2 defines an inner container for cigarettes. Attached to the outer case 2 by a hinge or fold line 3 is a flip-top 4. When the top 4 is flipped forward the container defined by the outer case 2 is closed and, as shown in Figure 1, when the top 4 is flipped back the inside of the container is open. Within the outer case 2 an inner frame 5 is inserted. The inner frame 5 acts as an extension of the sides of the outer case 2 and engages the top 4 when it is in the closed position. The inner frame 5 is formed from a front panel 6, the lower portion of which extends part way down into the container and is adhered to the front side7 of the outer case 2. In cases

where the inner frame extends the full length of the container adhesion is not necessary. The inner frame 5 has two parallel side portions 8a, 8b which extend along the inside of the side edges of the outer case 2. The side portions 8a, 8b are joined to the front panel the front panel 6 by a perforated fold line 9a, 9b. Elongate slots in the fold lines 9a, 9b form respective laterally extending tabs 10a, 10b on either side of the front panel 6 of the inner frame 5. The tabs 10a, 10b engage the inside face of the flip top 4 when it is in the closed position thereby retaining it frictionally in place.

As shown in Figure 1 the exposed top portion of the inner frame 5 is pre-printed with an image which is visible once the flip-top 4 is opened. The exposed part of the inner frame 5 can therefore be used for marketing messages and the like.

A blank 17 for forming the inner frame 5 is shown in Figure 2. The blank 17 has parallel sides 9,10 and opposite ends 11,12 with a notch 12a in the end 12 and a correspondingly shaped tab-like extension 13 at the other end 11. The notch 12 enables a user to view and gain access to the contents of the container of a flip-top carton in which an inner frame 5 formed from the blank 11 is inserted.

The tab-like extension 13 is the waste card from the notch of the next or previous blank in the production line. The blank 17 is formed from three panels; a main or central panel 14 on either side of which is a side panel 15a, 15b. The side panels 15a, 15b are attached to the main panel 14 by hinge lines 16a, 16b formed by a series of perforations through the thickness of the blank. An elongate shape slot lOa, 1Ob is cut out of the blank in line with the perforation 16a, 16b which define the hinge line. The

elongate slots 10a, 10b define the laterally extending tabs lOa, 1Ob on either side of the main panel 14 when the blank 11 is folded along the hinge lines 16a, 16b to form an inner frame by folding the two side panels 15a, 15b through 900 from their coplanar positions in the blank along the fold lines 9a, 9b, to form the inner frames.

One embodiment of apparatus according to the present invention is shown schematically in Figure 3. The apparatus comprises a supply reel 19 of board strip 20 which is drawn from the supply reel 19 over a diverter roller 21 and guide roller 22 to form an open loop 23 which ensures that there is no tension on the strip 20 as it passes between two transport rollers 24, 25, which are plain rollers one of which (the roller 24) is driven via a toothed belt (schematically illustrated by the line 26 from a servo motor 27.

From the nip between the plain rollers 24,25 the strip 20 passes between two pairs of perforator rollers comprising an anvil roller 28 and a cut and crease roller 29 which latter has four sets of perforating teeth 30, and four elongate slot-forming teeth 31, which is driven via a servo-motor 32. Other embodiments may have a different number of perforator teeth and slot-forming teeth.

The strip 20 then passes through another pair of plain rollers 33,34, driven by a servomotor 35 before passing under a photo detector 36 on its way to a separator blade 37 which is driven to reciprocate in synchronism with the incremental movements of the machine.

Packaging machines of this type operate on a basic indexed motion at, for example, four hundred steps per minute, although the indexed machine speed may increase to the region of eight hundred packs per minute with one index step representing the motion of the apparatus between one pack and the next, namely between one separating advancement of the cutter blade 37 and the next. Correspondingly, each of the transport rollers 24,25 and 33,34 are caused to rotate through an angle corresponding to the advancement of the strip 20 by a distance representing the length of the strip 20 between successive cuts of the blade 37, and the cut and crease roller 29 and anvil 28 correspondingly turn through the appropriate angle dependent on their diameters. As illustrated in Figure 3, the cut and crease roller 29 has two sets of perforating and slot-forming teeth such that the roller blade 29 will turn through 1800 at each advancing indexed movement.

The photo detector 36 is provided to detect the presence of print registration marks identifying the location on the strip 20 of printed images (not illustrated in Figure 3) positioned at regular intervals along the length of the strip 20.

In operation, due to unavoidable tolerances, the indexing movement of the transport rollers 24,25 and 33,34, as well as that of the perforating cutter and anvil 28,29 will not match exactly the separation between successive printed images represented by the separation of the print registration marks detectable by the photodetector 36. Upon detection of such a print registration mark the photodetector produces a signal which is fed to a central control unit 38 which also receives input signals from the motors 26,32, 35 indicating the phase angle of the shafts driving the transport rollers

24, 25 and 34, 33 as well as that driving the cut and crease roller 29 and its anvil 28.

These latter are otherwise synchronised to the machine speed via an encoder, such as an optical encoder sensing the angular position of each respective output shaft. The encoder signal for each shaft will thus have a predetermined value if the machine is synchronised with the images on the strip 20 when the registration mark passes under the photodetector 36. Any divergence from this predeterminable phase relationship is detected by the central control unit 38 and adjustment signals generated for bringing the phase angles back into synchronisation. If the divergence is detected as a delay in the arrival of the registration mark under the photodetector 36, that is if the registration mark arrives late the two pairs of plain nip rollers 24,25 and 33,34 are advanced by an angle corresponding at their periphery to the detected delay, and signals controlling advance of the motors 26 and 35 are only fed from the central control unit 38 when the detected phase angle of the motor 32 represents an angle of the cutter wheel 29 at which the elongate blade 31 is in contact with the strip 20.

Advancement of the strip 20 in relation to the cutter wheel 29 can thus take place by accelerating the nip rollers 24,25 and 33,34 whilst the strip 20 is engaged with the elongate blade 31 since any slight increase in the length of the slot formed by this blade will result only in a minor modification to the length of the tabs in the folded inner frame as described in relation to Figures 1 and 2.

Because the relationship between the tabs 10a, lOb (see Figure 1) must remain approximately in the correct position in relation to the end 12 (see Figure 2) the nip rollers are decelerated after the cut has been made by the cutter blade 37 in order to

return the board and cutter rollers 29 to their original relationship. In this way cumulative errors cannot build up.

If, when it arrives at the photodetector 36 the print registration mark is"early" demonstrating an advance of the strip which is too great in relation to the position of the image thereon, the blade 37 is displaced in the direction of advancement by a short distance corresponding to the error detected by the central control unit from the information supplied thereto on the phase angle of the motors. The cutter blade 37 is correspondingly displaced in the direction of advance of the strip 20 (represented by the arrow A in Figure 3) by a distance calculated by the central control unit 38 to compensate for this discrepancy. After its cutting stroke the blade 37 is then returned to the standard position for reciprocating motion in synchronism with the remainder of the machine. In this way the synchronisation of the machine with the printed images can be maintained to an accuracy in the region of + and-0.3 mm.

The duty cycle of the machine illustrated in Figure 3 is typically 50/50 and the central control unit causes the motors to act effectively as a Geneva drive, but controlled by software rather than a mechanical structure. It is important to appreciate that the adjustments to the registration are made continuously whilst the apparatus is in motion and does not require the apparatus to be stopped in order to make a synchronising adjustment.

Figure 4 illustrates an alternative form of inner frame which is adapted for use in cigarette packets having an opening in the front face thereof. In this drawing the front

panel 39 of the inner frame 40 has a v-notch 41 in the lower edge 42 which matches a rhomboidal opening 43 in the front face 44 of a cigarette packet 45. When the inner frame 40 is positioned in the packet 45 the v-shape notch 41 is aligned with the opening 43 so that the contents of the packet can be viewed through the opening as can be seen in Figure 5.

Figure 6 illustrates an alternative embodiment in which the perforator teeth and the separator blade are carried on a single roller 50 rather than being separate elements as in the embodiment of Figure 3.

In this embodiment the drum or roller 50 has the circumferential rows of perforator teeth 51,52 and a plurality of generally axially extending separator blades 53 spaced circumferentially about the roller 50. The shape of the separator blades 53 comprises a central axial section 54, two intermediate circumferential links 55,56 and two end sections 57,58. Each row of teeth 51,52 includes one generally C-shape elongate tooth 59 in circumferential alignment with the intermediate links 55,56 of the separator blade 53.

As in the embodiment of Figure 3, the registration adjustment takes place at the phase angle fo the rotation of the drum 50 corresponding to the engagement of the teeth 59 with the strip 20.

In an alternative embodiment, however, either with separate cutters for perforation and separation such as in Figure 3, or with cutters mounted-on a common drum or roller

as in Figure 6, one or more of the perforator teeth may be removed to give the possibility of effecting the registration adjustments when the drum 50 is in the angular orientation in which such (missing teeth would be in contact with the strip 20.

The present invention is advantageous as it provides a print registration system capable of varying the synchronisation of a pre-printed board in relation to a set of serrating rollers and an independent cutter. With the present invention it is possible to provide an inner frame for a flip-top carton having a pre-printed image which is exposed to view when the flip-top carton is opened. This opens up the possibility of promotional and marketing opportunities which were not previously possible. Errors in registration can be detected then the print position automatically adjusted within pre-set limits. Apparatus according to the present invention can be provided as an add-on, up-grade module or unit for use in existing packaging machinery.

Figure 7 illustrates a further alternative embodiment of the invention which differs from the embodiment of Figure 3 in the position of the drive rollers 24,25. In the embodiment of Figure 7 these rollers are positioned upstream of the slack loop 23 and a photocell and photodiode 46,47 sense the presence of the light in the crop.

The drive rollers 24,25 are thus driven to maintain the loop size, the signal from the photocell when the light enters between the photodiode 47 and the photodetector 46 acting momentarily to reduce the speed of the drive rollers 24,25 (or to stop them entirely) until the loop light 23 moves out of the line of sight of the photocell by the take-up of its rollers 34,35, whereupon drive to the rollers 24, 25 is reinstated. In this way a single photodetector pair is able to maintain the desired loop size without the need for a detector to sense a minimum allowable loop size. It also means that the web 20 is advantageously under the tension as it passes between the rollers 28,29.

Claims

CLAIMS 1. Apparatus for producing packaging blanks from a continuous strip of material having images printed at intervals therealong, in which at least one set of perforations are formed in the strip parallel to the length of the strip by a rotary perforator and a section of the strip is separated from the remainder thereof by a separator cutter to form a blank, in which periodic adjustments to the relative position of the strip and the separator cutter are made to maintain the registration of the images in relation to the separation line made by the said separator cutter without disengaging the perforator from the strip.
2. Apparatus as claimed in Claim 1, in which the perforator has a plurality of relatively shorter perforator blades for producing short perforations and at least one relatively longer perforator blade for producing an elongate perforation and the adjustments to the relative position of the strip and the perforator are made when the said longer blade is engaged with the strip.
3. Apparatus as claimed in Claim 1 or Claim 2, in which at least some registration adjustments are made by varying the relative position of the strip and the separator cutter.
4. Apparatus as claimed in Claim 3, in which the variations in the relative positions of the strip and the separator cutter are effected by displacing the separator cuter with respect to a fixed frame of reference.
5. Apparatus as claimed in Claim 4, in which the said separator cutter is returned to a reference position after separating a blank from the strip.
6. Apparatus as claimed in any preceding Claim, in which the adjustment for registration is a relative advancing movement of the strip in relation to the separator cutter or a displacement, in the advancement direction of the strip, of the separator cutter.
7. Apparatus as claimed in any preceding Claim, in which the strip is driven to advance by pairs of transport cutters on each side of the said rotary perforations, the transport rollers determining the transport speed of the strip and being themselves driven by respective independent electric motors.
8. Apparatus as claimed in Claim 7, in which the adjustment for registration is effected by accelerating the electric motors driving the strip transport rollers with respect to the motor driving the rotary perforator.
9. Apparatus as claimed in any of Claims from 7 to 8, in which there are further provided at least one pair of transport rollers in advance of the said strip transport rollers whereby to create an open loop in the strip between a reel thereof and the rotary perforator ensuring there is substantially no residual tension in the strip as it arrives at the strip transport rollers or the perforator.
10. Apparatus as claimed in any of claims from 7 to 9, in which the electric drive motions are stepped at a fixed duty cycle to match incremental advancing movements of a packaging machine of which the apparatus forms part.
11. Apparatus as claimed in Claim 10, in which the rotary perforator and the Q transport rollers are all independently driven by the said electric motors.
12. Apparatus as claimed in any preceding claim, in which the said separator blade and the said perforator blades are carried on a common roller or drum.
13. A method of producing printed blanks for a package from a continuous strip of material printed with images at intervals along its length, comprising the steps of perforating the strip parallel to its length with a rotary perforator, cutting the strip into blanks with a separator cutter, and periodically adjusting the relative longitudinal position of the strip and the separator cutter by causing relative displacement thereof while the perforator remains engaged.
14. A method as claimed in Claim 13 for use in apparatus in which the perforator has a plurality of shorter blades for producing short perforations and at least one longer blade for producing an elongate perforation, in which the step of adjusting the relative position of the strip and the perforator is conducted when the longer blade is engaged with the strip.
15. A method as claimed in Claim 13 or Claim-14, in which at least some

registration adjustments are made by varying the relative position of the strip and the separator cutter.
16. A method as claimed in Claim 15, in which the variations in the relative position of the strip and the separator cutter is effected by displacing the separator cutter with respect to a fixed frame of reference.
17. A method as claimed in Claim 16, in which the said separator cutter is returned to a reference position after separating a blank from the strip.
18. A method as claimed in any of Claim 13 to 17, in which the registration adjustment is effected by a relative advancing movement of the strip with respect to the cutter, or a displacement of the separator cutter in the advancing direction of the strip.
19. A method as claimed in any of Claims 13 to 18, in which the registration adjustments are effected by accelerating drive motors which drive strip transport rollers with respect to a drive motor which drives the rotary perforator.
20. A packaging blank produced from a strip of material by the method of any of Claims 13 to 19.
21. A packaging blank produced from a strip of material by the apparatus of any of Claims 1 to 12.
22. A cigarette packet having an inner frame with an image printed or otherwise formed on a part thereof exposed to view by the method of any of claims 13 to 19.
23. Apparatus for producing packaging blanks substantially as hereinbefore described with reference to, and as shown in the accompanying drawings.
24. A method of producing packaging blanks substantially as hereinbefore described with reference to the accompanying drawings.
25. A packaging blank substantially as hereinbefore described with reference to and as shown in the accompanying drawings.
26. A cigarette packet having an inner frame substantially as hereinbefore described and as shown in the accompanying drawings.