Abstract:
A web processing assembly including first, second and third fixed spaced apart pairs of nip rollers moving the web respectively at a first, second and third speeds, the first and third speeds being constant and similar, the second speed being variable with a mean speed similar to the first and third speeds, a first idler roller engaging the web between the first and second pair of rollers and a second idler roller engaging the web between the second and third pair of rollers, each idler roller maintaining the web in constant tension by moving along a restrained path perpendicular to its axis to compensate for a difference between the variable second speed and the respective one of the constant first and third speeds. A method for processing a web and system for conveying a web are also disclosed.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to web processing machines, particularly to semi-rotary web processing machines. 
     2. Background Art 
     Web processing machines using a rotating tool cylinder processing successive sections of a continuous web of material include for example machine performing die cutting, laminating, stamping, printing, and coating. The successive sections are usually identical (i.e. repeats), and can be for example shapes to be cut, printed images, etc. The rotating tool is usually required to have the same tangential speed as the linear speed of the web when the tool is used to process each section of the web. 
     When the speed of the tool cylinder rotation and of the web are constant, the length of one section of web to be processed is usually equal to the circumference of the tool cylinder. As such, changing the length of the sections usually implies changing the tool cylinder. To reduce costs, a number of semi-rotary processes have emerged, allowing the use of a single tool cylinder for various sizes of web section. In most cases however, the modules performing the semi-rotary process cannot be used in series with other modules, since the web exiting the module usually travels at an intermittent speed, and as such is not compatible with a rotary process. 
     In web processing it is often desirable to perform multiple operations on a web, for example printing, laminating and cutting, through the use of several modules, one per operation to be performed, installed in series, i.e. with the web circulating through the modules and from one to the other in a continuous fashion. However, in such series the modules are usually dependent on one another for maintaining the web in tension, and as such a registry error at one module is reflected in all the downstream modules. As such, registry of the web at each module can be a complex procedure, usually done through modifying the speed or position of the multiple tool cylinders. 
     SUMMARY OF INVENTION 
     It is therefore an aim of the present invention to provide an improved web processing machine. 
     It is also an aim of the present invention to provide an improved method for processing a web. 
     It is a further aim of the present invention to provide an improved system for conveying a web between a tool cylinder and a corresponding anvil cylinder. 
     Therefore, in accordance with the present invention, there is provided a web processing assembly for a web processing module, the assembly comprising first, second and third fixed spaced apart pairs of nip rollers moving the web at a first, second and third speeds, the first and third speeds being constant and similar, the second speed being variable with a mean speed similar to the first and third speeds, and a first idler roller engaging the web between the first and second pair of rollers and a second idler roller engaging the web between the second and third pair of rollers, each of the first and second idler rollers maintaining the web in constant tension by moving along a restrained path perpendicular to an axis of the respective one of the first and second idler rollers to compensate for a difference between the variable second speed and the respective one of the constant first and third speeds. 
     Also in accordance with the present invention, there is provided a web processing machine for processing a web of material having a series of successive sections to be processed, the web processing machine comprising a constantly rotating tool cylinder having a predetermined circumferential length with at least a portion of the circumferential length defining at least one raised tool for processing an individual one of the sections, the tool rotating at a given tool tangential speed, a first pair of rollers upstream of the tool cylinder, the first pair of rollers pressing the web material therebetween and driving the web material at a first constant speed a second pair of rollers upstream of the tool cylinder and downstream of the first pair of rollers, the second pair of rollers pressing the web material therebetween and driving the web material at a cycling speed following a cycle corresponding to one rotation of the tool cylinder, the cycling speed corresponding to a mean speed similar to the first constant speed, the cycle including a period of constant speed similar to the tool tangential speed where the web travels in synchronism with the at least one tool processing a respective one of the sections, and a period of variable speed performing a re-register of a next one of the sections with the tool for the next rotation of the tool cylinder, the tangential speed being a function of the mean speed such that the at least one tool will be in register with the respective one of the sections, and a third pair of rollers downstream of the second pair of rollers, the third pair of rollers pressing the web material therebetween and driving the web material at a third constant speed similar to the first speed. 
     Further in accordance with the present invention, there is provided a method of processing a web comprising the steps of conveying a web into a first processing module at a constant speed, conveying the web through the first processing module at a first speed while maintaining a first tension on the web, the first speed having a mean corresponding to the constant speed, processing the web with a rotating tool in the first processing module, conveying the web from the first processing module to a second processing module at the constant speed, conveying the web through the second processing module at a second speed while maintaining a second tension on the web, the second tension being independent of the first tension, the second speed having a mean corresponding to the constant speed; and processing the web with a second rotating tool in the second processing module. 
     Further yet in accordance with the present invention, there is provided a system for conveying a web between a tool cylinder and a corresponding anvil cylinder, the system comprising a first motor driving the web upstream of and in proximity to the tool cylinder, a second motor driving the anvil cylinder, the anvil cylinder driving the tool cylinder, a third motor driving the web upstream of the first motor, a fourth motor driving the web downstream of the second motor, a first sensor sensing the position of a section of the web in proximity of the tool cylinder and generating first position data, a second sensor sensing the position of the tool and generating second position data, and a controller receiving the first and second position data, directing the first motor to drive the web at a cycling speed according to the first and second position data, and directing each of the second, third and fourth motors to drive the web at a constant speed similar to a mean speed of the first motor. 
     Further yet in accordance with the present invention, there is provided a method of processing a web, the method comprising the steps of constantly rotating a tool cylinder with an anvil cylinder, the tool cylinder having a circumferential surface defining a tool, moving a web between the tool cylinder and the anvil cylinder at a variable speed, subsequently detecting the position of each section to be processed on the web, detecting the position of the tool for each of the sections to be processed, and re-registering each section to be processed with the tool by adjusting the variable speed according to the position of the tool and the position of the section to be processed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Reference will now be made to the accompanying drawings, showing by way of illustration a preferred embodiment of the present invention and in which: 
         FIG. 1  is a front view of a web processing module according to an embodiment of the present invention; 
         FIG. 2  is a front view of a web processing machine including the web processing module of  FIG. 1  placed in series with a similar web processing module; 
         FIG. 3  is a block diagram of the control system of the web processing module of  FIG. 1 ; 
         FIG. 4  is a flow chart illustrating the progression of the web in the web processing module of  FIG. 1  or, similarly, in the first web processing module of  FIG. 2 ; 
         FIG. 5  is a flow chart illustrating the progression of the web in the second web processing module of  FIG. 2 ; and 
         FIG. 6  is an alternative embodiment of the tension maintenance system for the web processing module of  FIG. 1 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to  FIG. 1 , a web processing module  10  according to the present invention is schematically shown. The web processing module  10  includes a body  14  supporting a web processing assembly  12 , an unwind roll  16  preferably including lateral registering means (not shown), a tool cylinder  78  driven by an anvil cylinder  80 , and rewind roll  24 . The web processing assembly  12  allows a web  20  to be pulled from the unwind roll  16  at a constant speed, processed by the rotating tool cylinder  78  at a cycling speed or a constant speed, as required, and rewound on the rewind roll  24  at a constant speed. The web  20  can be, for example, paper, plastic film, label stock, etc. The unwind and/or rewind rolls  16 , 24  can be omitted if the web processing module  10  receives the web  20  from and/or feeds the web  20  to another web processing module. 
     The tool cylinder  78  can be, for example, a printing cylinder, a stamping cylinder, a die cutting cylinder, an embossing cylinder, a coating cylinder, etc. The tool cylinder  78  preferably includes a changeable plate around at least part of its circumference, with the plate defining a raised tool on a portion of the circumference only. The portion of the circumference not occupied by the tool does not contact the web  20  when it is aligned therewith. The raised tool corresponds to the length of the sections of the web  20  to be processed, and as such the same tool cylinder  78 , with different plates, can be used with different section lengths. In a preferred embodiment, the tool cylinder  78  is magnetic, and the plates are flexible metallic plates adhered thereto. The anvil cylinder  80  is preferably a hardened steel roller and rotates at a constant speed. 
     The tool cylinder  78  can alternatively include a changeable plate defining a tool along its entire circumference. The tool can also be integral with the tool cylinder  7 , with the tool being defined along part of or the entire circumference of the tool cylinder  78 . The tool cylinder  78  can also be changed for a tool cylinder  78  of a different size, as required, without changing the remaining elements of the web processing assembly  12 . 
     As shown in phantom, the body  14  can also support unwind and rewind rolls  18 , 19  for lamination material  22 , which can be processed together with the web  20 . The body  14  can also support a plurality of additional rewind rolls  26 , 27  for the web  20  or for waste material  28  which could be, for example, the waste matrix created during the process of die cutting. 
     The web processing assembly  12  includes a first cassette  30  pulling the web material  20  from the unwind roll  16  or from another upstream process. The first cassette  30  includes a first drive roll  32 , a first nip roll  34  pressed against and under the first drive roll  32 , and preferably a first nip idler  36  under the first nip roll  34 . The first nip roll  34  is frictionally driven by the first drive roll  32 . The first cassette  30  is located just downstream of the unwind roll  16 , the web  20  being circulated from the unwind roll  16  in a “S” pattern under and around the idler  36 , and between the nip roll  34  and drive roll  32 . The nip roll  34  and drive roll  32  apply pressure to the web  20  so that it is essentially clamped, i.e. the web will not slide upon applying pressure thereto. The first cassette  30  pulls the web at a constant speed. 
     The web processing assembly  12  also includes, downstream of the first cassette  30 , a second cassette  38 . The second cassette  38  includes a second drive roll  40  and a second nip roll  42  pressed against and under the second drive roll  40  to be frictionally driven thereby. The second cassette  38  is located just upstream of the tool and anvil cylinders  78 , 80 , with a plane being nearly tangential to the top of the drive roll  40  and to the bottom of the tool cylinder  78 . The web  20  is circulated in a “S” pattern under the nip roll  42 , between the nip roll  42  and drive roll  40 , and over the nip roll  42  to go between the tool cylinder  78  and anvil cylinder  80  and over an idler roll  82  located downstream thereof. The nip roll  42  and drive roll  40  also apply pressure to the web so that it is essentially clamped. The second cassette  38  coordinates the movement of the web  20  with the constant rotating movement of the tool cylinder  78  such that each section to be processed is in register with the tool. The second cassette  38  pulls the web at a cycling speed. The mean value of the speed of the second cassette  38  is substantially equal to the constant speed of the first cassette  30 . In cases where the circumference of the tool cylinder  78  is the same as a length of an individual section of the web  20  to be processed, the cycling speed corresponds to a constant speed (i.e. rotary process). 
     The web processing assembly  12  also includes, downstream of the second cassette  38  and of the tool cylinder  78 , a third cassette  44 . The third cassette  44  includes a third drive roll  46  and a third nip roll  48  pressed against and under the third drive roll  46  to be frictionally driven thereby. The web  20  is circulated in a “S” pattern under the nip roll  48 , between the nip roll  48  and drive roll  46 , and over the nip roll  46  to go to the rewind roll  24  or to another downstream process. The nip roll  48  and drive roll  46  also apply pressure to the web so that it is essentially clamped. The third cassette  44  pulls the web at a constant speed substantially equal to the constant speed of the first cassette  30 . 
     The web processing module  10  can also include one or more additional cassettes  50  for driving lamination material, waste material, etc. 
     In order to maintain adequate tension of the web  20  between the cassettes  30 , 38 , 44  as well as to provide a smooth transition for the web  20  between the constant speed and the cycling speed, the web processing assembly  12  includes a tension maintenance system  122  including first and second dancer assemblies  52 , 54 . The first dancer assembly  52  includes a first set of arms  56 , the body of which preferably include a plurality of holes  58  for weight reduction purposes. The first set of arms  56  is pivotable about a first pivot  60  on one end, and supports a first idler roller  62  on the other end. The first idler roller  62  engages the web  20  between the first and second cassettes  30 , 38  and applies a given tension thereto. The second dancer assembly  54  similarly includes a second set of arms  64  with holes  66 , pivotable about a second pivot  68  and supporting a second idler roller  70 . The second idler roller  70  engages the web  20  between the second and third cassettes  38 ,  44  and applies the same given tension thereto. To maintain the tension, the first and second sets of arms  56 , 64  each include a bracket  72 ,  74  which are interconnected by an adjustable pneumatic cylinder  76 . 
     The first and second idler rollers  62 ,  70 , being each located between a constant and a cycling drive of the web  20 , undergo a reciprocating motion under the action of the web  20  and as such act as a transition between the two driving modes. This reciprocating motion is directed along a restrained arcuate path defined by the rotation of the first and second pivotable set of arms  56 , 64 . The idler rollers  62 , 70  maintain a constant tension on the web  20 , which is adjusted through the pneumatic cylinder  76 . 
     Numerous alternative configurations for the two idler rollers  62 ,  70  are also possible, one of which is the combination of the two pivots  60 ,  68  to have each set of arms  56 , 64  independently pivotable about a single pivot axis. 
     Another alternative configuration is illustrated in  FIG. 6 , where the first and second idler rollers  62 , 70  are respectively connected to a first and second cable or chain  86 , 88 . The two cables  86 , 88  are each directed by a respective pulley  90 , 92  and interconnected by the pneumatic cylinder  76 , so that the idler rollers  62 , 70  can undergo a vertical motion. Additional fixed idlers  94 , 96  direct the web  20  to accommodate the vertical motion of the idler rollers  62 , 70 . 
     Alternatively, the pulleys  90 , 92  can be replaced by additional fixed idlers orienting the web  20  to accommodate a horizontal motion of the idler rollers  62 , 72 , which are connected by cable or chain portions to the pneumatic cylinder  76 . 
     The idler rollers  62 ,  70  can also be separate from each other, with their movement being coordinated electronically. The pneumatic cylinder  76  can be replaced by other means to create tension, such as an hydraulic cylinder or a spring system. In any case, the idler rollers  62 ,  70  have to maintain the web  20  in tension while each is moveable along a restrained path perpendicular to its axis to compensate for the speed differential of the web  20 , with the tension of the web  20  preferably being adjustable. 
     The web processing assembly  12  is controlled through the system illustrated in  FIG. 3 . A controller  110  sends a speed signal to four electronically controlled motors  112 , 114 , 116 , 118  respectively driving the first drive roll  32 , second drive roll  40 , third drive roll  46  and anvil cylinder  80 , with the anvil cylinder  80  driving the tool cylinder  78  (see  FIG. 1 ). The signal sent to the first drive roll motor  112  is preferably the reference signal and as such is constant, so that the first drive roll motor  112  always rotates at the same constant speed. The third drive roll motor  116  and the anvil cylinder motor  118  both rotate at a constant speed, while the second drive roll motor  114  can rotate at a cycling speed, as will be further explained below. 
     While the web  20  is passing through the web processing assembly  12 , the controller  110  receives a plurality of signals allowing it to adjust the speed of the remaining motors  114 , 116 , 118 . A web sensor  84 , for example a contrast sensor, is preferably located in proximity to the second cassette  38 , as close as possible to the tool cylinder  78  (see  FIG. 1 ). This web sensor  84  determines the position of the section to be processed on the web  20 , and send a signal to the controller  110  accordingly. A tool sensor  120  is also preferably provided to read the position of the tool on the tool cylinder  78  and send a signal to the controller  110 . 
     In cases where the length of an individual section of the web  20  is different from the circumference of the tool cylinder  78 , the web processing assembly  12  will perform in a semi-rotary manner. The controller  110  sends a cycling speed signal to the second drive roll motor  114  to compensate for the difference between the portion of the circumference of the tool cylinder  78  not covered by the tool and the distance between successive sections to be processed in the web  20 . Thus, the cycling speed of the second drive roll motor  114  varies according to a cycle corresponding to a rotation of the tool cylinder  78 . When the web  20  is in contact with the tool to process one section, the second drive roll motor  112  will drive the web  20  at a constant speed which is equal to the tangential speed of the tool. When the web  20  is not in contact with the tool, the second drive roll motor  112  will drive the web  20  at a variable speed allowing the web  20  to “catch up” to or “wait” for the next rotation of the tool, depending whether the circumference portion of the cylinder  78  is longer or shorter than the length of an individual section to be processed in the web  20 . When the length of an individual section is shorter, the variable speed preferably includes a negative speed component, such that the web is intermittently “pulled back”. 
     The cycling speed can be fixed, i.e. calculated by the controller following parameters of the web section and tool such that each cycle is the same during the entire process. However, the controller  110  preferably adjusts the cycling speed for each cycle according to the data received by the web sensor  84  and the tool sensor  120  to re-register the web  20  with the tool at each web section to be processed, while maintaining a constant mean speed of rotation for the second drive roll motor  114 . The re-register allows corrections in register to be made upstream of the web processing, rather than conventional register done on measurements taken downstream of processing, i.e. after the web is processed in a misaligned manner and as such unusable. The re-register thus allow for a reduction in waste material. 
     In cases when the length of an individual section of the web  20  to be processed is equal to the circumference of the tool cylinder  78 , i.e. the tool covers the entire diameter of the tool cylinder  78 , the controller  110  can instruct the second drive roll motor  114  to rotate at a constant speed, and the web processing assembly  12  performs in a rotary manner. Preferably, the second drive roll motor  114  rotates at a cycling speed including a period of variable speed to re-register the web  20  with the tool upon receiving data from the web and tool sensors  84 , 120 . It is understood that the order of magnitude of the speed variation in this case will be significantly less than in the true semi-rotary process described above. 
     The controller  110  can also receive a feedback signal from the tension maintenance system  122 . The tension maintenance system  122  includes a first feedback device  124  monitoring the reciprocating movement of the first idler roller  62 , and a second feedback device  126  monitoring the reciprocating movement of the second idler roller  70 . The first and second feedback devices  124 , 126  are preferably respectively located at the first and second pivots  60 , 68  of the first and second set of arms  56 , 64  (see  FIG. 1 ). Upon adjustment of the pneumatic cylinder  76  to adjust the tension of the web  20 , the mean position of the reciprocating motion of the two idler rollers  62 , 70  will move away from a home position. For example, augmenting the pressure of the cylinder  76  will augment the web tension  20  and move the arms  56 , 64  downwardly, such that the mean position of the reciprocating motion of the two idler rollers  62 , 70  will drift down from its home position. The feedback devices  124 , 126  each send a signal to the controller  110  if such a change in the mean position of its respective idler roller  62 , 70  occurs. 
     In the absence of a signal from the feedback devices  124 , 126 , the controller  110  sets the speed of the second drive roll motor  114  so that the second drive roll  40  drives the web  20  at a mean speed equal to the constant speed of the web  20  at the first drive roll  32 . The controller also sets the speed of the third drive roll motor  116  such that the third drive roll  46  drives the web  20  at a constant speed equal to the constant speed of the web  20  at the first drive roll  32 . The mean speed of the web  20  throughout the entire web processing assembly  12  will be equal to the constant speed of the web  20  at the first and third drive rolls  32 , 46 . The controller  110  preferably sets the ratio between the mean speed of the web  20  and the constant tangential speed of the anvil cylinder motor  118  (and as such the constant tangential speed of the tool cylinder  78 ) to be proportional to a ratio between the length of an individual section of the web  20  to be processed and the circumference of the tool cylinder  78 . Preferably, the two ratios are equal, such that, for example, when the circumference of the tool cylinder  78  is double the length of an individual section of the web  20 , the tangential speed of the tool cylinder  78  is double the mean speed of the web  20 . When the circumference of the tool cylinder  78  and the length of an individual section of the web  20  are equal, the tangential speed of the tool cylinder  78  is equal to the mean speed of the web  20 , and the web  20  is processed in a rotary manner. 
     When a signal from the first feedback device  124  is received, indicating a change in center position of the first idler roller  62 , the controller  110  increments the speed of all the motors downstream to compensate for this change in center position until the center position of the reciprocating motion of the first idler roller  62  is back to its home position according to the first feedback device  124 . Thus, the mean speed of the second drive roll motor  114 , as well as the constant speed of the third drive roll motor  116  and of the anvil cylinder motor  118  are equally incremented. If a signal from the second feedback device  126  is received, indicating a change in center position of the second idler roller  70 , the controller  110  increments the speed of the motor downstream, i.e. the speed of the third drive roll motor  116 , until the center position of the reciprocating motion of the second idler roller  70  is back to its home position according to the second feedback device  126 . 
     In use, as illustrated in  FIG. 4  with reference to the preceding Figures, the web  20  passes through the web processing module  10  according to the following: first, a user  130  provides data to the controller  110  on the process to be performed, e.g. ratio of the length of individual sections of the web with respect to the circumference of the tool cylinder, constant speed of the web  20  at the first cassette  30  or speed of rotation of the tool cylinder  78 , etc., as indicated at  154 . The controller  110  then computes the profile for the process, including the cycling speed at the second cassette  38 , as indicated at  156 . The controller  110  performs a reset on the position of the web  20 , tool, and first and second idler rollers  62 , 70 , by slowly moving the web  20  according to data received by the web and tool sensors  84 , 120  as well as the first and second feedback devices  124 , 126 , as indicated at  158 . 
     The web  20  can now be processed. The web  20  is pulled from the unwind roll  16  at a constant speed by the first drive roll  32 , as indicated at  160 . The web  20  travels at constant speed to the first idler roller  62 . The center position A of the first idler roller  62  is detected by the first feedback device  124 , as indicated at  162 . The position B of the section of the web  20  near the tool cylinder  78  is detected by the web sensor  84  and the position C of the tool is detected by the tool sensor  120 , as indicated respectively at  164  and  166 . The controller  110  adjusts the cycling speed of the second drive roll motor  114  according to the tool and web section positions B and C to perform a re-register of the web  20  with the tool, and the mean cycling speed according to the first idler roller position A, as indicated at  168 . The web  20  is pulled at the cycling speed by the second drive roll  40 , as indicated in  170 . The speed of the anvil cylinder  80  is adjusted by the controller  110  according to the first idler roller position A, see  172 , and the web  20  is processed by the tool, as indicated at  174 . The web  20  travels at cycling speed to the second idler roller  70 . The center position D of the second idler roller  70  is detected by the second feedback device  126 , as indicated at  176 . The constant speed of the third drive roll motor  116  is adjusted by the controller  110  according to the first idler roller position A and the second idler roller position D, as indicated at  178 . The web  20  is pulled at the constant speed by the third drive roll  46 , as indicated at  180 . of course, since the web  20  is continuous, all the above-described operations are done simultaneously, but were described here following the progression of a reference point of the web  20  for ease of understanding. 
     The web processing module  10  can be used in series with other similar modules  11 . A series of two modules  10 , 11  is illustrated in  FIG. 2 . The rewind roll  24  for the web  20  is placed downstream of the second module  11 . The second module is similar in construction to the first module  10 , and as such will not be detailed here. The components of the second module  11  are represented by a reference numeral corresponding to the reference numeral of the corresponding component in the first module  10 , augmented by  200 . The drive rolls of the second module  11  are referred to as fourth, fifth and sixth drive rolls  232 , 240 , 246 ; the idler rollers, as third and fourth idler rollers  262 , 270 ; the feedback devices, as third and fourth feedback devices  324 , 326 , etc. 
     The controller  310  of the second module  12  is in communication and synchronized with the controller  110  of the first module  110 . Alternatively, a single controller can be used for both modules  10 , 11 . 
     When the module  10  is used in series with the similar module  11 , the third cassette  44  is preferably inactive, i.e. it does not drive the web and acts as an idler. Alternatively, the fourth cassette  230  can be inactive instead of the third cassette  44 . 
     Before circulating the web through the first or second modules  11 , 12 , the user  130  also provides data to the controller  310  of the second module on the process to be performed, as indicated at  155 . The controller  310  then computes the profile for the process as indicated at  157 . The controller  310  performs a reset on the position of the web  20 , tool, and first and second idler rollers  262 , 270 , by slowly moving the web  20  as indicated at  159 . The web  20  is circulated through the first module  11 , as indicated at  161  and as described above, except with steps  178  and  180  being omitted since in this case the third cassette  44  is inactive. 
     The web  20  then circulates through the module  11  according to the following: first, the web  20  is pulled from the first module  10  at a constant speed by the fourth drive roll  232 , as indicated at  182 , and travels at constant speed to the third idler roller  262 . The center position E of the third idler roller  262  is detected by the third feedback device  324 , as indicated at  184 . The position F of the section of the web  20  near the tool cylinder  278  is detected by the web sensor  284  and the position G of the tool is detected by the tool sensor  320 , as indicated respectively at  186  and  188 . The controller  110  adjusts the cycling speed of the fifth drive roll motor  314  according to the tool and web section positions F and G to perform a re-register of the web  20  with the tool, and the mean cycling speed according to the first idler roller position A, the second idler roller position D and the third idler roller position E, as indicated at  190 . The web  20  is pulled at the cycling speed by the fifth drive roll  240 , as indicated in  192 . The speed of the anvil cylinder  280  is adjusted by the controller  110  according to the first idler roller position A, the second idler roller position D and the third idler roller position E, see  194 , and the web  20  is processed by the tool, as indicated at  196 . The web  20  travels at cycling speed to the fourth idler roller  270 . The center position H of the fourth idler roller  270  is detected by the fourth feedback device  326 , as indicated at  198 . The constant speed of the sixth drive roll motor  316  is adjusted by the controller  110  according to the first idler roller position A, the second idler roller position D, the third idler roller position E and the fourth idler roller position H, as indicated at  200 . The web  20  is pulled at the constant speed by the sixth drive roll  246 , as indicated at  202 . 
     The tension in the web  20  can be advantageously adjusted to a different value in each module  10 , 11 , since the first module  10  is isolated in tension from the second module  11  by the third or fourth cassette  44 , 230 . The modules  10 ,  11  can also be used in a standard rotary manner, with the second and fifth drive rolls  40 , 240  pulling the web at a constant speed. As such, a plurality of modules such as  10  and  11  can be installed in series to perform multiple processes on a web, whether rotary or semi-rotary, each process being independent in tension from the others. The symmetry of the module  10  also allows for easily reversing of the direction of travel of the web  20  if another configuration is required. 
     The re-register step performed for each section also allows two modules such as  10 , 11  to be used independently, i.e. without having the web  20  run directly from one another, for a same web. For example, the first module  10  could print in each section of the web  20 , and the second module  11  could die cut in each section, while easily registering the previously printed sections with the die. 
     Since the web  20  exiting the web processing module  10  is tension isolated and has an independent re-register, the module  10  can also be used in series with any number of rotating web processing machines. 
     A conveyor can also be located just downstream of the tool cylinder  78  in cases when the tool cylinder  78  is a cutting cylinder performing through cut or sheeting, such as to convey the cut elements of the web  20 . In the case of through cut with matrix, the waste matrix passes through the second dancer assembly  54 , through the third cassette  44 , and is rewound on the rewind roll  24 . In the case of sheeting, i.e. the web  20  is completely cut at each section, the second dancer assembly  54  is not used since there is no more web after the sheeting step is performed, and as such the second arm  64  is locked in place. The cut sheets are conveyed by the conveyor from the tool cylinder  78 . 
     Other units, such as an infrared and/or ultraviolet drying unit, can be provided within the module  10  downstream of the tool cylinder  78 , or in series with the module  10 . 
     As mentioned above, the module  10  can thus easily be configured, by placing an appropriate tool plate around the tool cylinder  78 , to perform multiple operations such as, but not limited to, die cutting, laminating, printing, coating, slitting, underscoring, perforating, etc. The tool cylinder  78  can also include more than one tool along its circumference, with the web  20  being “backed up” between each tool by the second cassette  38 . In that case, the relation between the speed of the tool cylinder  78  and of the web  20  is adjusted accordingly. One example would be two separate perpendicular cutting dies, which would act on a same location on the section of the web  20  to perform a cross-shaped cut. 
     The embodiments of the invention described above are intended to be exemplary. Those skilled in the art will therefore appreciate that the foregoing description is illustrative only, and that various alternatives and modifications can be devised without departing from the spirit of the present invention. Accordingly, the present invention is intended to embrace all such alternatives, modifications and variances which fall within the scope of the appended claims.