Abstract:
A conversion unit converting a first continuous web substrate ( 2 ) into a second substrate in the form of converted blanks of predetermined length ( 3 ). On account of cutting tool rotation speed, the web ( 2 ) moves at various speeds for cutting the web cut lengths and other aspects of cutting and transport process having a constant input speed. The unit includes a first motorized arrangement ( 4 ) for producing a first run driving (F) of the web ( 2 ), a sheeter ( 12 ) having rotary tools ( 13, 14 ) for cutting the web into blanks ( 3 ), a second motorized arrangement ( 17 ) for producing a second run driving of the substrate ( 2, 3 ), the second arrangement being positioned in the immediate proximity of the sheeter ( 12 ), and at least one station ( 21, 22, 23 ) having rotary tools ( 26, 27, 28, 29, 32, 33 ) for converting the blanks ( 3 ). A speed of rotation ( 38, 41 ) of the second arrangement ( 17 ) varies during a cycle of rotation of the tools ( 13, 14 ) of the sheeter ( 12 ), comprising a phase at constant tangential speed ( 46 ), substantially equal to the speed of rotation of the tools ( 13, 14 ) of the sheeter ( 12 ), during which the cut is made, a speed reduction phase ( 43 ), during which a length of the web ( 2 ), dependent on the difference between the length of the blank ( 3 ) and an extension of the periphery of the tools ( 26, 27, 28, 29, 32, 33 ), is kept upstream of the second arrangement ( 17 ), and a speed increase phase ( 44 ), during which the substrate ( 2, 3 ) is discharged downstream of the second arrangement ( 17 ).

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a 35 U.S.C. §§371 national phase conversion of PCT/EP2014/001389, filed May 22, 2014, which claims priority of European Patent Application No. 13002773.3, filed May 29, 2013, the contents of which are incorporated by reference herein. The PCT International Application was published in the French language. 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to a unit for converting a first continuous web substrate into a second substrate in the form of blanks. The invention also relates to a packaging production machine equipped with a unit for converting a continuous web substrate into blanks. 
       TECHNICAL BACKGROUND 
       [0003]    A packaging production machine is intended for the manufacture of boxes, which then form the packaging, after folding and gluing. In this machine, a first initially planar substrate, such as a planar continuous web of cardboard, is unwound and is printed by a print unit, which is itself formed of sub-units in the form of printing units. 
         [0004]    The printed web is then transferred to a conversion unit producing in particular at least one of the following conversions: a cutting of the web into blanks, a cutting of the blanks into boxes, an embossing, a creasing, a stripping of the waste from the cutting process. A blank is formed of a number of boxes, which can be interconnected by nicks forming bridges made of the same material as the blank and the boxes. 
         [0005]    The blanks obtained are then separated into individual boxes. The boxes are then arranged shingled, before being stacked in rows so as to form piles in a delivery and palletizing station for the purpose of storage of the boxes or their transport from the production machine. 
         [0006]    All the conversions are performed in line or sequence in the conversion unit with successive conversion stations driven synchronously. Each station comprises rotary cylinders arranged in pairs. A rotary cylindrical upper tool, usually the male tool, cooperates with precision with a rotary cylindrical lower tool, known as the female tool. The web passes through the radial gap between the upper tool and the lower tool. 
         [0007]    The shaping and the circumference of each type of the tools are linked to the type of conversion procedure to be performed by the tools. The circumference of each type of tool is an integer multiple of the length of each box. This implies that each pair of tools is devoted to and usable only for the conversion procedure for which it has been designed. 
         [0008]    A tool has to be controlled long in advance of its operation, which is incompatible with the production changes currently required during the conversion. Moreover, a tool is very costly and is only profitable for producing extremely high production quantities. 
       PRIOR ART 
       [0009]    Document U.S. Pat. No. 3,926,097 describes a unit for carrying out conversions on a web substrate, while making it possible to use the same cylinders whatever may be the desired blank length in this unit, a first pair of tools forming a sheet cutter, also known as a “sheeter” makes a frontal cut, which allows the blank to be detached from the rest of the web. The unit then comprises at least one station including respective conversion tools that convert the blank that has just been separated and is arranged downstream of the sheeter. 
         [0010]    The tools of the sheeter and the conversion tools are obtained by assembling machined sheet steel plates to a metal cylinder, thus giving the male and/or female cutting and/or conversion shape. The plates are wrapped around and then attached to their respective cylinders by welding or by magnetic fixing. 
         [0011]    This solution using plates is less costly and can be implemented more quickly if the procedure is changed in order to convert new blanks. The cylinders are not disassembled with each conversion procedure change. The cylinders instead serve merely to support numerous different plates each devoted to anticipated conversion procedures. Compared with cylinders, the plates are lighter and can thus be handled more easily by the operators. This solution combines the throughputs obtained thanks to the uninterrupted rotary web supply for conversion with the flexibility of the die cutting conversion tools. 
         [0012]    In order to achieve detachment of the blank, the web is introduced in the unit by a loop control section that supplies the web to the unit at a clocked speed. The tools of the sheeter rotate at the same speed as the conversion tools. The plates of the sheeter and of the conversion tool cover only an angular sector of the periphery of the cylinders. Each pair of tools thus has an active angular sector, with which it performs its cutting or conversion procedure, and an inactive angular sector. 
         [0013]    A pair of drive rolls is provided upstream of the sheeter. These drive rolls are driven at a constant speed. These drive rolls rotate at a speed slightly higher than the maximum speed provided to the web by the loop control section at clocked speed. This overspeed makes it possible to maintain the tension of the web during the operation of the sheeter. 
         [0014]    However, there is a risk that the drive rolls will slide over the surface of the web. The printed surface or the lacquer on the surface of the web may become damaged, or the material forming the web will rip. In addition, due to the excessive speed of the drive rolls when the speed of the loop control section is at its minimum, the web is regularly over-tensioned, which may change its resilience. This leads to register losses between the printing and the cutting and the subsequent conversion or conversions. 
       SUMMARY OF THE INVENTION 
       [0015]    The primary object of the present invention lies in providing a conversion unit for converting a first continuous web substrate into a second substrate in the form of converted blanks. A second object is to produce a unit for converting a continuous web into blanks of a predetermined length using conversion cylinders of which the overall peripheral extension is greater than the length of a blank or the length of the format of the boxes constituting a blank. A third object is to overcome the technical problems mentioned for the prior art unit. A further object is that of successfully inserting a conversion unit into a packaging production machine. 
         [0016]    A conversion unit is used to convert a first continuous web substrate into a second substrate in the form of converted blanks of a predetermined length. The continuous web is fed at a constant speed into the conversion unit. The conversion unit comprises: 
         [0017]    a first motorized arrangement for producing a first run driving of the first continuous web substrate, 
         [0018]    a sheeter having rotary tools for cutting the first continuous web substrate into a second substrate in the form of blanks, 
         [0019]    a second motorized arrangement for producing a second run driving of the substrate, the second motorized arrangement being positioned in the immediate proximity of the sheeter having rotary tools, and 
         [0020]    at least one station having rotary tools for converting the second substrate in the form of blanks into converted blanks. 
         [0021]    In accordance with one aspect of the present invention the conversion unit is characterized in that a speed of rotation of the second motorized arrangement varies during a cycle of rotation of the rotary tools of the sheeter, the speed rotation comprising: 
         [0022]    a phase at constant tangential speed, substantially equal to the speed of rotation of the rotary tools of the sheeter; and during this phase at constant tangential speed, the first continuous web substrate is cut by the sheeter; 
         [0023]    a speed reduction phase during which a length of the first continuous web substrate is kept upstream of the second motorized arrangement; this length of the first continuous web substrate is dependent on the difference between the predetermined length of the blank and a peripheral extension or the total circumference of the conversion tools, and 
         [0024]    a speed increase phase during which the substrate is discharged downstream of the second motorized arrangement. 
         [0025]    The conversion is defined, in a non-limiting example, as being a cutting, a creasing, an embossing, a metallization by hot stamping, a gluing of labels or of holograms, a stripping of waste cut out beforehand, and yet others. The upstream and downstream directions are defined with reference to the running direction of the substrate in the conversion unit and in the packaging production machine. 
         [0026]    In other words, the clocked speed of the second motorized arrangement imposes the same clocked speed on the substrate, which makes it possible to hold and guide the substrate before, during and after the cutting procedure performed by the sheeter. The second motorized arrangement has an active role of holding the substrate, which is a continuous web, i.e. forming the first substrate, or is a blank, i.e. forming the second substrate. The modulation of speed also makes it possible to adapt the speed of the substrate to that of the sheeter in a first phase and to that of the conversion tools in a second phase. 
         [0027]    If one or more printer groups are arranged before the conversion unit, as applies to the majority of prior art machines, the peripheral extension of the conversion cylinders matches the rate of repetition of the printed design, i.e. the printed format of the blanks. In the present invention, the format of the tools is greater than the repetition of the printed format. 
         [0028]    The substrate is defined, in a non-limiting example, as being formed of a continuous web material, such as paper, flat cardboard, corrugated cardboard, laminated corrugated cardboard, flexible plastic, for example polyethylene (PE), polyethylene terephthalate (PET), bioriented polypropylene (BOPP), or other materials. 
         [0029]    In a further aspect, the invention also relates to a packaging production machine, comprising a unit having one or more technical features described and claimed hereinafter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    The invention will be understood and its various advantages and different features will become clearer upon reading the following description of a non-limiting exemplary embodiment provided with reference to the accompanying schematic drawings, in which: 
           [0031]      FIG. 1  shows a synoptic side view of a unit for converting a substrate in accordance with a first embodiment of the invention; 
           [0032]      FIGS. 2 and 3  show views of the unit of  FIG. 1  with different positions of the tools of the sheeter and of the conversion station respectively; 
           [0033]      FIGS. 4 and 5  show speed curves as a function of the cycle of rotation of the sheeter for the first embodiment and respectively for a first and a second blank length; 
           [0034]      FIGS. 6 and 7  show synoptic side views of a unit for converting a substrate in accordance with a second embodiment of the invention for a first and a second blank length respectively; 
           [0035]      FIG. 8  shows a speed curve as a function of the cycle of rotation of the sheeter for the second embodiment; and 
           [0036]      FIGS. 9 and 10  show a synoptic side view of a unit for converting a substrate in accordance with a third embodiment of the invention for a first and a second blank length. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0037]    As illustrated in  FIGS. 1 to 3, 6, 7, 9 and 10 , a unit for converting a substrate  1  converts a first substrate, in this case a continuous cardboard web  2 . The web  2  enters the unit  1  via its transverse upstream side, which is at the left in the Figures. The unit  1  cuts and converts the web  2  and delivers a second substrate in the form of converted blanks  3 , consequently formed of flat cardboard. The blanks  3  exit the unit  1  via its downstream transverse side. The direction of feed or of run driving (from left to right, shown by arrows F in the Figures) of the web  2  and of the blanks  3  in the longitudinal direction indicates the upstream direction and the downstream direction in the unit  1 . 
         [0038]    A packaging production machine comprises the conversion unit  1 . Upstream of the conversion unit  1 , the packaging production machine (not visible in the figures) has, by way of example, an unwinding drum, a printing unit with at least one printer group, and means for controlling the quality and the register. A lateral guidance of the web can be used to correct, where necessary, the lateral register of the web  2 . A distributor roll is intended to establish a constant tension of the web  2 . 
         [0039]    In a first embodiment of the invention ( FIGS. 1 to 3 ), the conversion unit  1  may firstly comprise, upstream, a first motorized drive arrangement  4  for run driving the web  2  in a clocked manner in the longitudinal direction F. The web  2  arrives from the printing unit and from the printer group at constant speed. The first motorized arrangement  4  advantageously may be a loop control arrangement. 
         [0040]    The loop control arrangement may favorably comprise a traction system, i.e. a primary drive roll  6 , also known as a “feathering drive”. Combined with the primary roll  6 , the loop control arrangement may comprise a loop control, i.e. a satellite roll  7 . 
         [0041]    The primary drive roll  6  is driven in rotation and turns (arrow R in  FIG. 3 ) on a primary shaft  9  driven by a primary electric drive motor. The primary shaft  9  and thus the primary roll  6  are mounted substantially horizontally and perpendicularly to the direction of run driving of the web  2 . The primary roll  6  thus drives the web  2  continuously from upstream to downstream. A press roll  8  keeps the web  2  positioned against the traction system  6 . The first motorized arrangement  4  comprises upstream an introduction roll  11 , similar to a press roll, ensuring the tension of the belt  2  at the input. 
         [0042]    The loop control is a satellite roll  7  mounted in a manner coupled in parallel to the primary roll  6 . The web  2  is engaged between the primary roll  6  and the satellite roll  7 . The web  2  is held there and can be driven at the same time. The web  2  travels over a path accounting for approximately three quarters of the revolution of the primary roll  6  and half the revolution of the satellite roll  7 . 
         [0043]    The satellite roll  7  is able to oscillate (arrow O in  FIGS. 1 and 3 ) about the primary roll  6 , from upstream to downstream and conversely from downstream to upstream. Two end positions of the satellite roll  7  are shown in dashed lines in  FIG. 1 . 
         [0044]    The amplitude of the oscillations O determines the kept and accumulated lengths of web  2  corresponding to the future blanks  3 . The frequency of the oscillations O of the satellite roll  7  generates variations of speed of the web  2 . The web  2  passes cyclically from a constant speed to a zero speed, and conversely from a zero speed to a constant speed. These variations of speed and the frequency of the oscillations (O) are selected in accordance with the speed of the cutting and conversion that follows. Examples for the first motorized arrangement  4  are known from documents CH-602.462, CH-618.660, EP-742.170 and WO-2010/063&#39;353. 
         [0045]    The conversion unit  1  then comprises a sheeter  12  for cutting the web  2  into successive blanks  3 . The sheeter  12  is positioned downstream of the first motorized arrangement  4 . The sheeter  12  comprises an upper cutting tool  13  and a smooth lower tool  14 , forming a counter-tool, also known as an anvil. 
         [0046]    The cutting tool  13  turns at the same speed as the lower tool  14 . The two tools  13  and  14  are motorized, by one or two independent motors. In the first embodiment a speed of rotation of the tools  13  and  14  of the sheeter  12  is preferably constant and greater than the speed at which the web  2  is fed into the unit  1 . 
         [0047]    A frontal cutting plate  16  is fixed to the surface of the cylinder of the upper cutting tool  13 . The plate  16  is equipped with cutting threads. The plate  16  has a transverse length substantially equal to the width of the web  2 . The plate  16  with its threads extends over a sector of small angular dimension over the cylinder. The threads have a zigzag shape, which is dependent on the shape of the front edge of the blank  3  and on the shape of the rear edge of the preceding blank. The web  2  is driven in the longitudinal direction F only when it is in contact with the cutting plate  16 . 
         [0048]    In the first embodiment of the invention ( FIGS. 1 to 3 ), the conversion unit  1  also comprises a second motorized drive arrangement  17  for driving the web  2  in the longitudinal direction F. This second motorized arrangement  17  can be positioned in immediate proximity, and in this case in proximity to and upstream of the sheeter  12 . This second arrangement  17  may advantageously be inserted between the first motorized arrangement  4  and the sheeter  12 . 
         [0049]    The second motorized arrangement  17  may preferably comprise a lower drive roll  18  driven in rotation by an electric drive motor. The second motorized arrangement  17  may also comprise upper press means for pressing the web  2  against the drive roll  18 . These press means may comprise a single upper pressure roller or a series of upper pressure rollers  19 . The drive roll  18  and the upper pressure roller(s)  19  form a system of intake or pinch rollers, which makes it possible to hold and guide the web  2 . This web  2  is engaged, held, pinched and driven between the drive roll  18  and the pressure rollers  19 . The second motorized arrangement  17  may be of the type described in document WO-2010/066&#39;325. 
         [0050]    The unit  1  then comprises at least one station for converting the blanks  3 , wherein the station has rotary tools. In the three embodiments shown in  FIGS. 1 to 3, 6, 7, 9 and 10 , three stations  21 ,  22  and  23  are used. The three stations  21 ,  22  and  23  are arranged in line, one after the other, and the blanks  3  are converted successively. 
         [0051]    A first conversion station may be an embossing station  21  for the blanks  3 , is positioned downstream of the sheeter  12 . The embossing station  21  comprises an upper male embossing tool  24  and a lower female embossing tool  26 , which turn at the same speed. The two embossing tools  24  and  26  are motorized. 
         [0052]    A male embossing plate  27  is fixed to the surface of the cylinder of the upper embossing tool  24 . The plate  27  is equipped with a male embossing die, having a shape that corresponds to the layout of the blank  3  and of the desired embossed boxes. The plate  27  with its male die extends over all or part of the surface of the cylinder of the upper embossing tool  24 . 
         [0053]    Similarly, a female embossing plate (not shown) is fixed to the surface of the cylinder of the lower embossing tool  26 . The female embossing plate is equipped with a female embossing die shaped complementary to the male embossing die and corresponding to the layout of the blank and of the desired embossed boxes. The female plate with its female die also extends over an angular sector of dimensions substantially equal to those of the male plate  27 . The web  2  is driven in the longitudinal direction F only when it is in contact with the male and female embossing plates  27 . 
         [0054]    A second conversion station may be a creasing and cutting station  22 , for creasing folds of the blanks  3 , cutting out the blanks  3  and to thus obtain the boxes. The creasing and cutting station  22  is positioned downstream of the embossing station  21 . The creasing and cutting station  22  comprises an upper male creasing and cutting tool  28  and a lower female creasing and cutting tool  29 . The upper creasing and cutting tool  28  turns at the same speed as the lower creasing and cutting tool  29 . The two creasing and cutting tools  28  and  29  are motorized. 
         [0055]    A male creasing and cutting plate  31  is fixed on the surface of the cylinder of the upper creasing and cutting tool  28 . The male creasing and cutting plate  31  is equipped both with a creasing die and male cutting threads, shaped to correspond to the layout of the blank  3  and of the desired creased and cut boxes. The plate  31 , with its die and its male threads extends over all or part of the surface of the cylinder of the upper creasing and cutting tool  28 . 
         [0056]    Similarly, a female creasing plate (not shown) is fixed to the surface of the cylinder of the lower creasing and cutting tool  29 . The female creasing plate is equipped with a female creasing die, shaped complementary to the male creasing die and corresponding to the layout of the blank and of the desired creased and cut boxes. The plate with its female die also extends over a sector of dimensions substantially equal to those of the male plate  31 . The web  2  is driven in the longitudinal direction F only when it is in contact with the male and female creasing and cutting plates  31 . 
         [0057]    A third conversion station may be a waste material removal station  23 , to remove areas of waste material present on the blanks  3  and to thus obtain the boxes. The removal station  23  is positioned downstream of the creasing and cutting station  22 . The removal station  23  comprises an upper removal tool  32  and a lower removal tool  33 , which turn at the same speed. The two removal tools  32  and  33  are motorized. 
         [0058]    A removal sector  34  is fixed to the surface of the cylinder of the lower removal tool  33 . The sector  34  is equipped with a series of radial needles capable of sinking into each piece of cut waste material. The needles separate the waste materials from the blank  3  by entraining these materials with the rotation of this lower tool  33  equipped with needles. The needles are positioned on the sector  34  and thus on the lower tool  33  in accordance with the layout of the blank  3  and of the desired cut boxes. The sector  34  with its needles extends over all or part of the cylindrical surface of the upper removal tool  32 . 
         [0059]    Holes are provided at different locations over the entire surface of the upper removal tool  32 . The holes can be formed directly in the metal cylindrical body of the upper removal tool  32 . The holes can be formed in a soft coating of a vulcanized rubber type covering the surface of the cylinder of the upper removal tool  32 . The holes can be formed in a plate then connected on the surface of the cylinder of the upper removal tool  32  or directly on the cylinder in more simple cases. The positions of the holes corresponds to the layout of the blank  3  and of the desired cut boxes and thus to the layout of the needles of the lower tool  33 . These needles come to be housed in the holes during the rotation of the two tools  32  and  33 , so as to effectively spike the waste material. The upper tool  32  and lower tool  33  ensure the transport of the blanks  3  and the retention thereof during the piercing of the waste material. 
         [0060]    This waste material is then released from these radial needles during the rotation of the lower tool  33 . To do this, ejectors in the form of fixed cones (not shown) are arranged parallel to the lower tool  33 . The radial needles are thus relieved of waste material and the needles thereafter sink into other waste material of the following blank  3  during the next revolution of the lower tool  33 . 
         [0061]    The conversion station(s) is/are a cutting station  22  for cutting blanks  3  into boxes, and/or an embossing station  21  for embossing blanks  3 , and/or a creasing station  22  for creasing blanks  3  and/or a removal station  23  for removing waste material. All the variations are thus possible for the tools  24 ,  26 ,  28 ,  29 ,  32  and  33  of the conversion station(s)  21 ,  22  and  23 . The first conversion station, i.e. embossing station  21 , is optionally formed in accordance with the type of desired boxes. A single station may also comprise both an embossing tool and a creasing tool. One station can be dedicated specifically to creasing and another additional station can be dedicated to the cutting. One station may comprise an upper cutting tool cooperating with a lower removal tool. 
         [0062]    The blank  3  cut into boxes attached simply by connection points in the cutting and creasing station  22  is more fragile. The blank  3  is held for its transport to the waste material removal station  23 . A first conveyor  36  of the conveyor belt and/or of the vacuum belt type can be inserted between the cutting and creasing station  22  and the waste material removal station  23 . The blank  3  cut into boxes attached simply by connection points and without waste material exiting from the waste material removal station  23  is more fragile. The blank  3  is held for its subsequent transport outside the conversion unit  1 . A second conveyor  37  of the conveyor belt and/or vacuum belt type can be positioned downstream of the waste material removal station  23 . 
         [0063]    The packaging production machine may have a blank separator, positioned downstream of the waste material removal station  23  and therefore downstream of the conversion unit  1 . The blanks  3  are separated there into individual boxes. 
         [0064]    The diameter of the upper tools  24 ,  28  and  32  and lower tools  26 ,  29  and  33  is sufficiently large to provide a significant peripheral extension. All the tools  24 ,  26 ,  28 ,  29 ,  32  and  33  have an equal peripheral extension corresponding to the maximum possible length for the blanks  3 . The possibility of converting blanks  3  having different lengths is dependent on the angular sector and therefore on the length of the selected plates  27 ,  31  and  34 . 
         [0065]    It is particularly favorable if the rotary tools of the sheet-cutter  12  and/or the rotary tools of the conversion station or of the conversion stations  21 ,  22  and  33  are mounted in a cassette. With a cassette, the operator can change the tools outside the station and thus outside the packaging production machine. The cassette allows the operator to easily prepare the station for the following operations in accordance with needs, i.e. in accordance with the layout of the blanks and/or of the boxes, alongside ongoing production. 
         [0066]    The cassette comprises two upper bearings holding, for rotation, the upper tool  13  or  24  or  28  or  32 , and fixed respectively to two lower bearings holding the lower tool  14  or  26  or  29  or  33 . The removable cassette can be introduced into a frame of the conversion station and can be fixed to the frame. Conversely, the removable cassette can be uncoupled and removed from said frame. 
         [0067]    A speed of rotation of the tools  24 ,  26 ,  28 ,  29 ,  32  and  33  and of the conversion station(s)  21 ,  22  and  23  is preferably constant and greater than the speed at which the web  2  is fed into the unit  1 . The loop control arrangement  4  enables the speed of the web  2  to be constantly adjusted so as to be adapted to the constant angular speed of the tools of the sheeter  12  and of the conversion station(s)  21 ,  22  and  23 . 
         [0068]    In accordance with the invention, the second motorized arrangement  17  has a variable speed profile for the substrate, in this case the web  2 . The second motorized arrangement  17  is thus a modulated insertion roll.  FIG. 4  concerns the speed profile  38  and the acceleration  39  of the second arrangement  17  for a minimum blank length  3 .  FIG. 5  concerns the speed profile  41  and the acceleration  42  of the second arrangement  17  for a maximum blank length  3 . 
         [0069]    In the first embodiment of the invention (see  FIGS. 1 to 5 ), due to the position of the second arrangement  17 , a first speed-reduction phase  43  of the second arrangement  17  is implemented after the last cut by the sheeter  12 .  FIG. 1  shows the relative position of the control loop  4  and the tools  24 ,  26 ,  28 ,  29 ,  32  and  33  when the cutting tool  13  of the sheeter  12  has just finished cutting the web  2 . 
         [0070]    In the first phase  43 , the control loop  4  starts to retreat with the objective of accumulating the web  2  arriving from the printing unit and of storing the web momentarily before sending it for the cutting process. A determined length of web  2  is accumulated upstream of the second arrangement  17 . This length of web  2  is dependent on the difference in length between the length of the blank  3  and the extension of the circumference of the tools  26 ,  27 ,  28 ,  29 ,  32  and  33 . 
         [0071]    While the appropriate length of web  2  is gathered, a gap G is thus produced between the web  2  arriving for the following blank and the blank  3  that has just been cut. While the appropriate length of web  2  is gathered, the blank  3  that has just been cut is driven and simultaneously converted by the tools  24 ,  26 ,  28 ,  29   32  and  33  in the stations  21 ,  22  and  23 . The maximum necessary gap G matches the difference between the length of the blank  3  and the circumference of the tools  24 ,  26 ,  28 ,  29 ,  32  and  33 . 
         [0072]    In the first embodiment of the invention (see  FIGS. 1 to 5 ), due to the position of the second arrangement  17 , a second speed increase phase  44  of the second arrangement  17  is implemented before the next cut by the sheeter  12 .  FIG. 2  shows the relative position of the control loop  4  and of the tools  24 ,  26 ,  28 ,  29 ,  32  and  33  when the cutting tool  13  of the sheeter  12  is at approximately 30° before the cut of the web  2 . In the second phase, the control loop  4  starts to advance (arrow O) with the objective of accelerating the web  2  at the same speed as that of the cutting tool  13 . The web  2  is withdrawn downstream of the second arrangement  17 . 
         [0073]    In a third phase  46 , the tangential speed of the second motorized arrangement  17  is constant and is substantially equal to the speed of rotation of the tools  13  and  14  of the sheeter  12 . The cut is performed during this third phase.  FIG. 3  shows the cutting tool  13  of the sheeter  12  in a position in which it is finishing its cutting of the web  2 . At this moment, the speed of the web  2  must be the same as the tangential speed of the tools  24 ,  26 ,  28 ,  29 ,  32  and  33 . 
         [0074]    In a second embodiment of the invention (see  FIGS. 6 and 7 ), the conversion unit  47  may comprise firstly upstream a first motorized drive arrangement  48 . The web  2  arrives from the printing unit and the printer group at constant speed. The first arrangement  48  may advantageously unroll the web  2  at constant speed in the longitudinal direction F. The first arrangement  48  is mechanically substantially similar to the second arrangement  17  described for the first embodiment of the invention. 
         [0075]    The sheeter  12  of the second embodiment is mechanically identical to that described for the first embodiment of the invention. In the second embodiment a speed of rotation of the tools  13  and  14  of the sheeter  12  is preferably modulated. The speed of the tools  13  and  14  is constant and must be substantially identical to that of the web  2  at the moment of the frontal cut due to the low angular dimension of the plate  16 . The speed of the tools  13  and  14  is variable with acceleration and deceleration in the rest of the perimeter so as to ensure the synchronization in terms of position with the following blank. 
         [0076]    In the second embodiment the conversion unit  47  also comprises a second motorized drive arrangement  49  for driving the substrate i.e. the web  2  and the blank  3 , in the longitudinal direction F. This second arrangement  49  can be positioned in immediate proximity, and can be positioned in this case in proximity and downstream of the sheeter  12 . This second arrangement  49  may advantageously be inserted between the sheeter  12  and the first of the conversion stations  21 . 
         [0077]    The second arrangement  49  is mechanically substantially similar to the second arrangement  17  described for the first embodiment of the invention. The second arrangement  49  may thus be mechanically similar to the first arrangement  48 . The substrate, i.e. the web  2  and the blank  3 , is engaged, held, pinched and driven between the lower drive roll  18  and the upper pressure rollers  19 . 
         [0078]    The three conversion stations  21 ,  22  and  23  of the second embodiment are identical to those described for the first embodiment of the invention. Similarly to the first embodiment of the invention, the packaging production machine may also have a blank separator positioned downstream of the waste material removal station  23  and therefore downstream of the conversion unit  47 . The blanks  3  are separated here into individual boxes. 
         [0079]    In accordance with the invention, the second motorized arrangement  49  has a variable speed profile for the substrate, in this case the web  2  and the blank  3 . The second motorized arrangement  49  is thus a modulated output roll.  FIG. 8  concerns the speed profile  51  and the acceleration  52  of the second arrangement  49 . 
         [0080]    In the second embodiment of the invention (see  FIGS. 6 to 8 ), a first speed increase phase  53  of the second arrangement  49  is implemented after the last cut by the sheeter  12 , due to the position of the second arrangement  49 . 
         [0081]    The blank  3  that has just been cut is accelerated and driven by the second arrangement  49  so as to reach the same speed  54  as that of the tools  24 ,  26 ,  28 ,  29 ,  32  and  33  of the conversion stations  21 ,  22  and  23 . A gap G is thus produced between the web  2  arriving for the following blank and the blank  3  that has just been cut. The maximum necessary gap G matches the difference between the length of the blank  3  and the circumference of the tools  24 ,  26 ,  28 ,  29 ,  32  and  33 . 
         [0082]    In the second embodiment of the invention (see  FIGS. 6 to 8 ), due to the position of the second arrangement  49 , a second speed reduction phase  56  of the second arrangement  49  is implemented before the following cut by the sheeter  12 . During this speed reduction phase  56 , a determined length of web  2  is accumulated upstream of the second arrangement  49 . This length of web  2  is dependent on the difference in length between the length of the blank  3  and the extension of the circumference of the tools  26 ,  27 ,  28 ,  29 ,  32  and  33 . In a third phase  57  the tangential speed of the second arrangement  49  is constant and is substantially equal to the speed of rotation of the tools  13  and  14  of the sheeter  12 . The cut is made during this third phase  57 . 
         [0083]    The first arrangement  48  and the sheeter  12  are mounted so as to be longitudinally movable (arrow L in  FIGS. 6 and 7 ), for example in a sliding frame  58  on rails  59  so as to vary the distance between the sheeter  12  and the conversion station  21  depending on the desired length for the blanks  3 .  FIG. 7  specifically shows the configuration for the maximum length of the blank  3 . The frame  58  is in its farthest left-hand position in  FIG. 7 , the space between the frame  58  and the second arrangement  49  or the first conversion station  21  being open to the greatest possible extent. 
         [0084]    In a third embodiment of the invention (see  FIGS. 9 and 10 ), the conversion unit  61  may comprise firstly upstream a first motorized drive arrangement  48 . The web  2  arrives from the printing unit and the printer group at constant speed. The first arrangement  48  is mechanically substantially similar to the first arrangement  48  described for the second embodiment of the invention and to the second arrangement  17  described for the first embodiment of the invention. The first arrangement  48  may favorably unroll the web  2  at constant speed in the longitudinal direction F. 
         [0085]    The sheeter  12  of the third embodiment is mechanically identical to that described for the first and second embodiments of the invention. In the third embodiment and as for the second embodiment, a speed of rotation of the tools  13  and  14  of the sheeter  12  is preferably modulated. 
         [0086]    In the third embodiment the conversion unit  61  also comprises a second motorized drive arrangement  62  for driving the substrate, i.e. the web  2  and the blank  3 , in the longitudinal direction F. This second arrangement  62  can be positioned in immediate proximity and can be positioned in this case in proximity and downstream of the sheeter  12 . This second arrangement  62  may advantageously be inserted between the sheeter  12  and the first of the conversion stations  21 . 
         [0087]    The second arrangement  62  is mechanically substantially similar to the second drive arrangement  17  described for the first embodiment of the invention and to the first motorized arrangement  48 . The substrate, i.e. the web  2  and the blank  3 , is engaged, held, pinched and driven between the lower drive roll  18  and the upper pressure rollers  19 . 
         [0088]    The three conversion stations  21 ,  22  and  23  of the third embodiment are identical to those described for the first and second embodiments of the invention. Similarly to the first and second embodiment of the invention, the packaging production machine may have a blank separator positioned downstream of the waste material removal station  23  and therefore downstream of the conversion unit  61 . The blanks  3  are separated here into individual boxes. 
         [0089]    In the third embodiment the conversion unit  61  may preferably also comprise a third motorized arrangement  63  for driving the substrate, i.e. the web  2  and the blank  3 , in the longitudinal direction F. This third arrangement  63  can be positioned in immediate proximity and can be positioned in this case in proximity and downstream of the sheeter  12 . This third arrangement  63  may advantageously be inserted between the sheeter  12  and the second arrangement  62 . 
         [0090]    The third arrangement  63  is mechanically substantially similar to the second arrangement  17  described for the first embodiment of the invention. The third arrangement  63  may thus be mechanically similar to the first arrangement  48  and to the second arrangement  62 . The substrate, i.e. the web  2  and the blank  3 , is engaged, held and driven between the lower drive roll  18  and the upper pressure rollers  19 . 
         [0091]    As can be seen in  FIG. 10 , the second arrangement  62  is mounted so as to be longitudinally movable (arrow T in  FIG. 10 ). This makes it possible to vary the distance between the second arrangement  62  and the sheeter  12  in accordance with the length of the blank  3  or the web  2  constituting the future blank. The first arrangement  48  and the sheeter  12  are mounted in a stationary manner, for example in a frame  58  fixed on a base  64 . 
         [0092]      FIG. 10  specifically shows the configuration for the maximum length of the blank  3 . The third arrangement  63  can thus be disconnected. The third arrangement is deactivated for example by raising the pressure rollers  19  (arrow U in  FIG. 10 ) and by lowering the drive roll  18  (arrow D in  FIG. 10 ), thus making it possible to distance the rollers and roll from the web  2 . This makes it possible for only the second arrangement  62  to be providing an active drive, this being dependent on the length of the blank  3  or of the web  2  constituting the future blank. 
         [0093]    In accordance with the invention, the second motorized arrangement  62  and/or the third arrangement  63  have a variable speed profile for the substrate, in this case the web  2  and the blank  3 .  FIG. 8  concerns the speed profile  58  and the acceleration  52  of the second arrangement  62  and/or of the third arrangement  63 . 
         [0094]    In the third embodiment of the invention (see  FIGS. 8 to 10 ), a first speed increase phase  53  of the second arrangement  62  and/or of the third arrangement  63  is implemented after the last cut by the sheeter  12 , due to the position of the second arrangement  62  and/or of the third arrangement  63 . 
         [0095]    The blank  3  that has just been cut is accelerated and driven by the second arrangement  62  and/or by the third arrangement  63  so as to reach the same speed  54  as that of the tools  24 ,  26 ,  28 ,  29 ,  32  and  33  of the conversion stations  21 ,  22  and  23 . A gap G is thus produced between the web  2  arriving for the following blank and the blank  3  that has just been cut. The maximum necessary gap G matches the difference between the length of the blank  3  and the extension of the circumference of the tools  24 ,  26 ,  28 ,  29 ,  32  and  33 . 
         [0096]    In the third embodiment of the invention (see  FIGS. 8 to 10 ), a second speed reduction phase  56  of the second arrangement  62  and/or of the third arrangement  63  is implemented before the following cut by the sheeter  12 , due to the position of the second arrangement  62  and/or of the third arrangement  63 . During this speed reduction phase  56 , a determined length of web  2  is accumulated upstream of the second arrangement  49 . This length of web  2  is dependent on the difference in length between the length of the blank  3  and the circumference of the tools  26 ,  27 ,  28 ,  29 ,  32  and  33 . 
         [0097]    In a third phase  57 , the tangential speed of the second arrangement  62  and/or of the third arrangement  63  is constant and is substantially equal to the speed of rotation of the tools  13  and  14  of the sheeter  12 . The cut is made during this third phase  57 . 
         [0098]    The present invention relates to three technical solutions aimed at providing the conversion unit  1 ,  47  and  61 , which, on the basis of the continuous web substrate  2 , make it possible to arrive at a substrate in the form of a blank  3 . The three solutions are aimed at ensuring a constant speed of rotation of the conversion tools  21 ,  22  and  23 , which carry the knives or the other elements for conversion, such as creasing, embossing or waste material removal, in spite of the fact that the format of these tools is generally larger than the repetition of the printed format. 
         [0099]    The present invention is not limited to the embodiments described and illustrated. Numerous modifications can be made, without departing from the scope defined by the set of claims.