Patent Publication Number: US-7222436-B1

Title: Process for perforating printed or embossed substrates

Description:
FIELD OF THE INVENTION 
   The present invention relates to a process for registering indicia with lines of termination in a sheet material. The lines of termination may be perforations or a chop-off which ends a first sheet and starts a second sheet, such sheets being typically presented in roll form. Indicia may be visual, such as printed inks or embossments, or may be functional, such as adhesive. 
   BACKGROUND OF THE INVENTION 
   Sheets for household use are well known in the art. It is often desirable to decorate such sheets, such as by printing. Printing can impart an aesthetically pleasing pattern to the sheet. Alternatively, the sheet may be embossed to impart an aesthetically pleasing pattern which is also tactually discernible. 
   Such sheets are typically made in continuous form and then later cut to discrete lengths as desired. Such cutting to discrete lengths may occur at the point of use, such as is caused by the consumer detaching one sheet from the balance thereof at a line of termination. For this purpose, the line of termination typically comprises a line of weakness, such as a perforation. Alternatively, the continuous sheet may be cut into discrete portions prior to the point of use. Such arrangement often occurs in individual napkins or facial tissues that are cut during manufacture and purchased by the consumer as discrete units. 
   It has been relatively facile in the prior art to register indicia with a cross-machine direction of such sheets while such sheets are transported in a continuous fashion during manufacturing. However, it is difficult to register the indicia in the machine direction and particularly difficult to register the indicia with lines of termination of such sheet materials. 
   One manner in which the foregoing difficulties have been addressed is to keep the length of the sheet material disposed between application of the indicia and the deposition of lines of weakness therein relatively short. However, this approach does not provide for feasibility in manufacturing processes, can require smaller sized equipment, and is infeasible where any modules necessary to impart such lines of weakness, or for the application of the indicia, provide a web path that is large enough to cause improper spacing between the indicia and the lines of weakness. 
   Other processes may provide acceptable results with regard to processing of a single type of web material, such as short sheets, but not work acceptably where longer sheet lengths are required. For example, one approach provides for a relatively short path length between the point at which the latter of the indicia and/or lines of termination are applied or imparted to the sheet and the point at which the continuous sheet is cut into separate discrete units at the point of manufacture. However, where relatively longer sheet lengths are required (i.e., rolled products, such as toilet tissue or paper toweling), difficulties are introduced by the cumulative error that occurs over the length of the continuous sheet. For example, a misregistration of 0.001 inches at the first repeat unit will provide a misregistration of 1 inch after the manufacture of 1,000 inches of sheet material. 
   The processes of the prior art provide for even larger problems when a parent roll being processed is exhausted and a new parent roll is started. A parent roll is a large roll of product that is later converted to multiple individual sheets by the apparatus and process disclosed herein. It should be known to those of skill in the art that different parent rolls have different properties which can affect the transport of the sheet through a manufacturing apparatus. By way of example, the amount of stretch in the sheet material as it travels through the apparatus frequently varies greatly between different parent rolls. As these properties vary, so does the registration of the indicia with the lines of termination. Such variations in registration must be accounted for in the manufacturing process. 
   Accordingly, it should be apparent to those of skill in the art that the approaches that may be feasible when dealing with longer sheet lengths are not sufficient for dealing with registration difficulties that occur in shorter sheet lengths and vice versa. Thus, it would be useful to provide a mechanism for overcoming these problems associated with misregistration between indicia and lines of termination in products having longer unit lengths and, in particular, core wound paper products and yet be flexible enough to deal with discrete articles of relatively short unit length. Additionally, it would be useful to provide for adjustments to the spacing between indicia and lines of termination while the sheet is being processed into consumer goods. 
   SUMMARY OF THE INVENTION 
   The present invention provides for a process for registering lines of termination with indicia in a transported sheet of web material. The process comprises the steps of: (a) transporting the sheet of web material in a first direction; (b) applying indicia to the sheet from a print cylinder, the print cylinder having a first angular position; (c) imparting lines of termination to the sheet of web material with a rotatable blade, the rotatable blade having a second angular position; (d) calculating a position error by comparing the first angular position of the print cylinder and the second angular position of the rotatable blade; and, (e) adjusting the second angular position of the rotatable blade according to the position error. 
   An alternative embodiment for the present invention comprises the steps of: (a) transporting the sheet of web material in a first direction; (b) applying indicia to the sheet of web material from a print cylinder, the print cylinder having a first angular position; (c) imparting lines of termination to the sheet of web material with a perforation cylinder, the perforation cylinder having a second angular position, the lines of termination being spaced from the indicia in a spacing; (d) calculating a position error by comparing the first angular position of the print cylinder and the second angular position of the perforation cylinder; and, (e) adjusting the second angular position of the perforation cylinder according to the position error in order to maintain the spacing within a desired range. 
   Yet another alternative embodiment for the present invention comprises the steps of: (a) transporting said sheet of web material in a first direction; (b) applying indicia to said sheet of web material from at least a first print cylinder having a first angular position; (c) imparting lines of termination to said sheet of web material with at least a first perforation cylinder having a second angular position, wherein said indicia and said lines of termination are disposed upon said sheet of web material relative to each other such that an indicia/lines of termination registration is created; (d) measuring an angular position of a first print cylinder and translating said position into a digital signal; (e) measuring an angular position of a first perforation cylinder and translating said position into a digital signal; (f) comparing said digital signal of said first print cylinder and said digital signal of said first perforation cylinder to provide a position error; and, (g) correcting said angular position of said first perforation cylinder according to said position error in order to maintain said indicia/lines of termination registration within a desired range. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
       FIG. 1  is a schematic perspective view of an apparatus according to the present invention having control signals designated by dash lines and mechanical connections designated by solid lines; and, 
       FIG. 2  is an elevational schematic view of an apparatus according to the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   As used herein, a “unit” is defined as that portion of the sheet that is discrete as delivered to the consumer. For example, this would include, but not be limited to, a single table napkin, a single roll of paper toweling, a single facial tissue, or a single roll of bath tissue. 
   As used herein, “continuous” means a relatively long product produced in a mostly continuous manufacturing process. A preferred but non-limiting example of a continuous product for use in the present process or apparatus is a rolled sheet where the length of the sheet on the roll is very long in relation to its width. The roll may or may not have a fixed length but becomes substantially continuous by splicing webs together to allow the process to run for much longer lengths of time. 
   As used herein, a “web” or a “sheet” refers to any thin, permeable, or impermeable substrate consistent and intended for use with the present invention. A web or sheet is characterized in being much longer in the machine direction than in the cross-machine direction and is generally handled in rolls of substrate. Such a web or sheet has two surfaces—a first or top surface and a second or back surface—as processed through the equipment. 
   A “stretchable substrate” refers to any material including, but not limited to, paper, polymeric or plastic films, cloths, or fabrics, woven materials, non-woven materials, laminates, and combinations thereof that stretch when subjected to a tensile force. 
   The term “registration” means the degree to which the indicia and lines of termination are disposed on the substrate in a specific relationship to one another. The relationship may be one where the indicia and lines of termination are separated from each other. However, the relationship may also be considered to be one where the indicia and the line of termination overlap resulting in a synergistic visual interaction between the image and/or line of termination. A perfect registration or registration with zero error occurs when the indicia and the line of termination are disposed onto a substrate in exactly the specific designated relationship to each other. Thus, it follows that the term “misregistration” means the degree to which the relative location of the indicia and line of termination are not in the specific designated relationship to each other. 
   The term “machine direction” is the term of art used to define the dimension on the processed sheet parallel to the direction of travel that the sheet takes through the machine consistent with use of the present invention. The term “cross-machine direction” refers to the dimension on the sheet perpendicular to the direction of travel through the machines and co-planar thereto. 
   Sheet  12 , according to the present invention, is generally planar, soft, and absorbent. The sheet  12  is generally suitable for use in applications such as bath tissue, paper toweling, placemats, napkins, facial tissue, and the like. The sheet  12  is preferably wound in roll form; however, can be provided in discrete units. In a preferred embodiment, the sheet  12  is cellulosic and preferably paper. However, sheet  12  in the form of films, foils, metal, and the like are also consistent with use of the instant invention. Cellulosic sheets can be made and/or processed in a manner consistent with U.S. Pat. Nos. 4,191,609; 4,637,859; and 5,245,025. 
   As illustrated, the sheet  12  is preferably manufactured in a continuous process and then later cut into discrete units according to how the final product will be distributed to the consumer. Discrete units can include roll products, such as paper toweling and bath tissue, as well as individual sheets, such as table napkins and facial tissue. The sheet  12  is preferably presented to the consumer as an individual unit having a sheet length. 
   The product is preferably presented to the consumer in roll form convolutely wound in a spiral about a core to yield a core wound paper product. The core wound paper product has a length taken in the principal or machine direction. Indicia  14  and lines of termination  16  are disposed in spaced relation throughout the sheet  12 . The indicia  14  may be intermediate or straddle adjacent lines of termination  16 . Coincident with each line of termination  16  is a leading edge  18  and a trailing edge  20  of the sheet  12 , the leading edge  18  being ahead of the trailing edge  20  in the manufacturing process. 
   In a preferred embodiment, the sheet  12 , according to the instant invention, is presented to the consumer as convolutely wound or rolled paper product. Such a product is suitable for use as paper toweling, bath tissue, facial tissue, napkins, and the like. The sheet  12  may have a length in the principal direction of at least 500 inches, preferably at least about 700 inches, more preferably at least about 900 inches, and most preferably at least about 1,100 inches. 
   Referring to  FIG. 1 , and shown schematically in  FIG. 2 , intermediate the lines of termination  16  that define the length of the sheet  12 , may be disposed a plurality of lines of termination  16  which provide a line of weakness. Preferably, such lines of weakness comprise perforations  22 . The perforations  22  may be spaced on a pitch of about 4.0 to 20 inches, with a preferred pitch of about 4.5 to 14 inches, and a more preferred pitch of about 12.0 to 12.5 inches. The perforations  22  are generally oriented in the cross-machine direction and are generally orthogonal to the direction of transport of the sheet  12  through the apparatus  10 . Preferably, but not necessarily, the perforations  22  extend throughout the width of the product formed by sheet  12 , as measured between the longitudinal axis  26  of the sheet  12 . 
   In such an embodiment, the indicia  14  are maintained in space relationship to the perforations  22 . Preferably, the indicia  14  are registered between the perforations  22  and juxtaposed with both the leading edge  18  and trailing edge  20  of the sheet  12 . In this manner, symmetry about the cross-machine direction centerline of the sheet  12  is obtained. Optionally, indicia  14  may be registered with the longitudinal edges  26  of the sheet  12  so that symmetry about the machine direction centerline of the sheet  12  is also obtained. 
   The length of a sheet  12  is its unfolded dimension taken in a first direction. The first direction is coincident with the machine direction of the sheet  12  during its manufacture and while in continuous form. The first direction is also the principal direction of the sheet  12  length. Plies or layers making up the sheet  12  are not separated when determining its overall length. Lines of termination  16  are the lines separating the sheet  12  into discrete units if such separation has not been performed at the time of manufacture. Typical lines of termination  16  may include both perforations  22  and chop-off cuts  24 . Perforations  22  are generally lines of weakness that allow separation of the sheet  12  into discrete units by the consumer as required. Chop-off cuts  24  separate an individual sheet  12  from an adjacent sheet  12  in the manufacturing process or terminate one roll and start the succeeding roll in the manufacturing process. 
   Preferably, the lines of termination  16  (particularly, the perforations  22 ) are oriented in the cross-machine direction and are transverse to the first direction of transport of the sheet  12 . Alternatively, it will be recognized that lines of termination  16 , having a diagonal orientation or having any other spaced relationship in the machine direction, may be utilized. 
   Two longitudinal edges  26  connect the leading edge  18  and trailing edge  20 . The longitudinal edges  26  are oriented substantially in the longitudinal or first direction. As shown, the longitudinal edges  26  are generally straight and parallel, and leading edge  18  and trailing edge  20  are generally straight and parallel. It should be recognized by one of ordinary skill in the art that, depending upon the arrangement used to cut the longitudinal edges  26  from the trim of the sheet  12 , the longitudinal edges  26  need not be either straight or parallel, as shown in the preferred embodiment. Likewise, the leading edge  18  and trailing edge  20  need not be straight or parallel, as shown. 
   The sheet  12  is transported through the apparatus  10  by any suitable means. Typically, the sheet  12  is drawn through the apparatus  10  under tension. Tension may be applied to the sheet  12  by winding it about a rotatable reel. The rotatable reel may be cylindrical and driven by an electric motor at a predetermined angular velocity. 
   Juxtaposed with the leading edge  18  and trailing edge  20  of the sheet  12  and generally oriented in a second direction, which is within the plane of the sheet  12  and generally orthogonal to the first direction (i.e., cross-machine direction), are indicia  14 . The indicia  14  are spaced from the lines of termination  16  so that a spaced relationship is formed therebetween. The spaced relationship is predetermined and may be adjusted during manufacture. The indicia  14  may be aesthetically pleasing and printed either in a single color or in a plurality of colors. Alternatively, the indicia  14  may be embossed upon sheet  12 . 
   Preferably, the indicia  14  are applied to the sheet  12  while it is being transported through the apparatus  10 , as described infra. The indicia  14  may be applied to the sheet  12  by any means known in the art suitable for the application of spaced indicia  14  at a predetermined repeating interval. In a preferred embodiment, the indicia  14  are printed onto the sheet  12  from a rotatable cylinder. The rotatable cylinder may be driven about a central axis  30  at a predetermined angular velocity. Suitable printing processes known in the art include gravure printing and flexographic printing. A print cylinder  28  or other means for the application of indicia  14  to the sheet  12  may be used. Such a print cylinder  28  may be driven by any suitable means, such as an electric motor. 
   If it is desired to emboss the indicia  14  onto the sheet  12 , any embossing technique known in the art would be suitable. Such embossing processes are described in U.S. Pat. Nos. 3,414,459; 3,556,907; and 5,294,475. 
   In an alternative embodiment, the indicia  14  may impart functional properties to the sheet  12  rather than visual or aesthetically pleasing properties. In such embodiment, the indicia  14  may comprise adhesive as, for example, would be used to join two plies together to form a sheet  12  having a double thickness. Alternatively, functional indicia  14  can be used to change properties at one portion of the sheet  12  relative to another portion of the sheet  12 . For example, adhesive used to join the tail of a core wound product to the periphery of the product may be applied to the sheet  12 , as well as adhesive used to join the leading edge  18  of a sheet  12  to the core about which the sheet  12  is wound. 
   Additionally, known additives that increase the softness, wet strength, temporary wet strength, hydrophobicity, hydrophilicity, or other property that functionally affects any other property of the sheet  12  may be applied thereto. 
   Typically, the means for the application of indicia  14  need only have the capability of applying the indicia  14  in spaced apart relationship in the first direction and to apply the indicia  14  at a frequency yielding indicia  14  at predetermined repeating intervals. The indicia  14  may be applied by any suitable system. However, a particularly preferred embodiment utilizes a rotatable print cylinder  28  driven to rotate about a central axis  30 , as described supra. 
   In addition to indicia  14  being applied at repeating intervals spaced apart in the first direction and in spaced relationship to the lines of termination  16 , indicia  14  may be juxtaposed with one or both of the longitudinal edges  26 . If each of the leading edges  18  trailing edges  20  and longitudinal edges  26  has indicia  14  juxtaposed therewith, a border is formed in the sheet  12 . This border can define and enhance the appearance or functionality of the sheet  12 . 
   The lines of termination  16  may be applied by any suitable means for imparting lines of termination  16  to the sheet  12 . The suitable means should also apply the lines of termination  16  at a frequency that yields predetermined repeating intervals. As noted above, the lines of termination  16  may totally separate the continuous sheet  12  into discrete units or may provide lines of weakness, such as perforations  22 . Suitable means for imparting the lines of termination  16  to sheet  12  include blades that are generally orthogonal to and impart lines of termination  16  generally orthogonal to the first direction of transport of the sheet  12  and which define adjacent leading edges  18  and trailing edges  20  of successive sheets  12 . A suitable means for imparting lines of termination  16  comprises a rotatable blade  32  driven about a central axis  34  at a predetermined angular velocity on a perforator roll. Naturally, one or more rotatable blades  32  may be driven on a common shaft, as is known in the art. 
   If the line of termination  16  is a chop-off  24 , it may be accomplished by two rotatable rolls juxtaposed together. The two rotatable rolls may comprise a chop-off roll  36  and a bedroll  38 , as is known in the art. Of course, even if the lines of termination  16 , which are the subject of the instant invention, are perforations  22 , the apparatus  10  will likely still comprise a chop-off roll  36  and a bedroll  38  to separate adjacent sheets  12 , each having a plurality of perforations  22 . Such rotatable blades  32  or any other means selected for imparting lines of termination  16  upon sheet  12  may be driven by any suitable means, such as an electric motor. If a both a perforator blade and a chop-off blade are used in the apparatus  10 , they may be driven by independent motors or by a common motor. A first type of motor suitable for use with the present invention comprises one or more draw or drive motors that impart an angular velocity to one or more rotatable components of the apparatus  10 . Such a motor may be connected to the rotatable component through a differential  52 . A differential  52  may comprise a mechanical drive capable of altering the angular velocity of an output shaft  54  to a desired degree of resolution of the base line angular velocity. The output shaft  54  of the differential  52  is preferably coupled to the rotatable component. 
   A second type of motor suitable for use with the instant invention is a correction motor—typically, a servo motor. This type of motor preferably drives a cage of the differential  52  so that the angular velocity of the cage is superimposed with the angular velocity of the input shaft  56 . Such super position can yield a very accurate and well controlled angular velocity at the output shaft  54 . Such correction motors can be precisely and accurately adjusted to the particular angular velocity independent of the angular velocity of the draw or drive motor. Moreover, as the angular velocity of the draw or drive motor changes, compensation can be made by the correction motor as the sheet  12  is being transported through the apparatus  10  without interruption of the transport of the sheet  12 . Compensation can be also be made as the sheet  12  is being transported through the apparatus  10  and without interruption of the transport of the sheet  12  should web tension change or should any other factor change the spaced relationship between the lines of termination  16  and the indicia  14 . 
   The lines of termination  16  and indicia  14  may be imparted and applied to the sheet  12 , respectively, in any desired order. However, the latter of the lines of termination  16  and indicia  14  to be imparted or applied to the sheet  12  constitutes the operation controlled by the apparatus  10  to maintain the desired spaced relationship therebetween. By way of example, the indicia  14  are applied to the sheet  12 . Then, the lines of termination  16  are imparted to the sheet  12 . If the sheet  12  has both perforations  22  and a chop-off cut  24 , typically the perforations  22  are imparted prior to the chop-off cut  24 . In the above described system, having the indicia  14  applied first, the desired spacing of the lines of termination  16  relative to the indicia  14  is achieved and maintained by adjusting the placement of the lines of termination  16  rather than by adjusting the placement of the indicia  14 . 
   The apparatus  10  of the instant invention may also comprise a sheet length correction motor  40 . The sheet length correction motor  40  controls the angular velocities of the rotatable blade  32 , chop-off roll  36 , and bedroll  38 . If the product is supplied as a convolutely wound product as, for example, is common with paper toweling and bath tissues, the sheet length correction motor  40  may further control the angular velocity of an indexing turret (not shown) and any core loading functions of that turret. The turret winds the product onto the core and performs the other functions ancillary to core winding, such as core loading onto a mandrel, applying adhesive to the core, chop-off of the sheet  12 , applying tail seal adhesive to the end of the sheet  12 , and the like. It is preferred that the differential  52  be disposed functionally intermediate the sheet length correction motor  40  and the rotatable blade  32  that imparts the lines of termination  16  to the sheet  12 . 
   Referring again to  FIG. 1 , and as shown schematically in  FIG. 2 , the apparatus  10  of the present invention preferably comprises a means for measuring the angular location of the print cylinder  28  and translating that location into a digital signal  42 . Such a system could be used on either of the print cylinder  28  or rotatable blade  32  or the chop-off roll  36  and bedroll  38 . This method preferably provides for a proximity switch  44  that senses a flag  46  or other marker disposed upon the print cylinder  28  or the central axis  30  cooperatively associated thereto. The proximity switch  44  creates a digital signal  42  for each revolution of print cylinder  28  or the central axis  30  cooperatively associated thereto. A suitable proximity switch  44  is available from Turck, Inc. A preferred, but non-limiting, embodiment of the present invention uses a model Ni5-G12-AN6X-H1141 inductive proximity switch. As would be readily recognized by one of skill in the art, multiple flags  46  or other markers may be disposed upon print cylinder  28  or central axis  30  cooperatively associated thereto in order to provide for increased resolution of the angular position of print cylinder  28  or to provide for more advanced timing needs as required by the process or sheet  12  utilizing apparatus  10 . 
   The apparatus  10  further comprises a means for determining the position of the rotatable blade  32  or the print cylinder  28 , whichever occurs later in the process. A device suitable for determining such a position is a position resolver  48  cooperatively associated with the rotatable blade  32  or other component, such as the chop-off roll  36  and/or bedroll  38  that is controlled in response to an error signal. 
   A suitable position resolver  48  is capable of determining angular position within at least 0.1 degrees. In a preferred embodiment, the position resolver  48  provides for 4,096 pulses per rotation. A suitable, but non-limiting, position resolver  48  is Reliance model number 57C360 available from Rockwell Automation. In a particularly preferred, but non-limiting, embodiment, the resolver may be used in conjunction with a resolver input module such as Reliance model number 57C411 manufactured by Rockwell Automation. If desired, an encoder can be substituted for the position resolver  48 , provided appropriate control logic, as is known in the art, is utilized. As would be readily recognized by one of skill in the art, multiple position resolvers  48  may be cooperatively associated with the rotatable blade  32  or other component(s), such as the chop-off roll  36  and/or bedroll  38  in order to provide for increased resolution of the angular position of the rotatable blade  32  or other component or to provide for more advanced timing needs as required by the process or sheet  12  utilizing apparatus  10 . 
   The apparatus  10  of the instant invention may further comprise a signal comparator  50 . The signal comparator  50  is capable of subtracting two input signals to produce an error signal. The first input signal to the signal comparator  50  is the angular position at least once per revolution of print cylinder  28  provided by proximity switch  44  disposed upon print cylinder  28  or the central axis  30  cooperatively associated thereto. The digital signal  42  may be provided in seconds based upon the speed of rotation of print cylinder  28  having a flag  46  or other marker disposed thereon or the central axis  30  cooperatively associated thereto. A suitable signal comparator is programmatically created within machine hardware and processed via a processor module. An exemplary, but non-limiting, processor module suitable for use with the present invention that can execute such a signal comparator program is a Reliance model number 57C435 AutoMax 7010 Processor, manufactured by the Rockwell Automation. 
   The second input signal to the signal comparator  50  can be the angular position of rotatable blade  32  used for imparting lines of termination  16  to the sheet  12 . The signal comparator  50  preferably subtracts the two input signals to yield an error signal. The apparatus  10  preferably makes the desired correction based upon the error signal. It would be known to one of skill in the art to convert the error signal to provide the desired correction using the sheet length correction motor  40 . Preferably, when the error signal exceeds a pre-set value, the apparatus  10  makes the desired correction. The pre-set value is preferably the desired spacing between the indicia  14  and lines of termination  16 . Apparatus  10  provides such correction by providing a change in speed of an appropriate motor, such as the sheet length correction motor  40 . 
   The appropriate motor adjusts the placement of the lines of termination  16  on the sheet  12  so that the lines of termination  16  may be brought closer to, or further from, the indicia  14 , thereby changing the spaced relationship therebetween. Such correction occurs while the sheet  12  is being transported through the apparatus  10  and without interruption of the transport. This moving correction is feasible because the appropriate motor is adjusted while it turns at a predetermined angular velocity. Alternatively, the means for changing the spaced relationship between the indicia  14  and the lines of termination  16  may incorporate changes to the path length of the sheet  12  through the apparatus  10 . The path length of the sheet  12  may be changed by use of an idler roll, the application of tension to the sheet  12 , and incrementally changing the angular velocity of either or both of the print cylinder  28  or the rotatable blade  32 . A more complete discussion on the processes by which to change the path length of the sheet  12  between the print cylinder  28  and the rotatable blade  32  are described in U.S. Pat. No. 6,928,929. 
   It should be recognized by those of skill in the art that the spacing and/or registration between indicia  14  and lines of termination  16  can be physically measured during production or after production of sheet  12 . Data from such physical measurements can be provided to apparatus  10  to provide for additional feedback regarding the registration between indicia  14  and lines of termination  16 . One of skill in the art could identify that part of indicia  14  that allows for such measurements within the sheet  12  either during manufacturing (in situ) or after processing of sheet  12 . 
   One of ordinary skill in the art will recognize that any of the foregoing means for changing the spaced relationship between the indicia  14  and the lines of termination  16  upon sheet  12  can be collectively considered as a means for changing the phase of the lines of termination  16  relative to the indicia  14  or vice versa. Such a change of phase can be accomplished by changing the phase of one or both of the means for imparting the lines of termination  16  or the means for applying the indicia  14  to the sheet  12  by introducing a temporary increase or decrease in the correction motor  40 . It is in this way that a change in the position of a given line of termination  16  relative to a given indicia  14  and vice versa. 
   In operation, the sheet  12  is moved relative to the apparatus  10 , preferably by holding the apparatus  10  stationary and drawing the sheet  12  through the apparatus  10  in the machine direction. The sheet  12  may be drawn through the apparatus  10  with the motor driving any suitable roll or rolls which frictionally engage the sheet  12  as it is drawn through the apparatus  10 . A draw motor can be used in conjunction with a draw correction motor for this purpose. 
   Process 
   In a preferred embodiment of the present invention, the first step performed by the apparatus  10  is the application of indicia  14  to the sheet  12 . The indicia  14  may be applied by a rotatable print cylinder  28  having a predetermined angular velocity, such as is used in flexographic or gravure printing. A rotatable print cylinder  28  is preferably driven independently from the draw motor and/or draw correction motor used to transport the sheet  12  through the apparatus  10 . 
   The second step performed by the apparatus  10  is detection of the angular position of print cylinder  28 . Detection of the angular position of print cylinder  28  or the central  30  axis cooperatively associated thereto is performed by a proximity switch  44  that senses the presence or absence of a flag  46  or other marker disposed upon print cylinder  28  or the central axis  30  cooperatively associated thereto. 
   The third step performed by the apparatus  10  is to impart the lines of termination  16  to the sheet  12 . The lines of termination  16  are placed on the sheet  12  in spaced relationship to the indicia  14 . The spacing is in the first or machine direction. The lines of termination  16  are preferably perforations  22  but may be chop-off cuts  24 . The lines of termination  16  are preferably oriented in the cross-machine direction. 
   The fourth step performed by the apparatus  10  is determination of the position of the perforations  22 , chop-off cuts  24 , or other lines of termination  16 . This determination is made by knowing the position of the rotatable blade  32  which imparts the perforations  22 , chop-off cuts  24 , or other lines of termination  16  to the sheet  12 . The position of the rotatable blade  32  is given by a position resolver  48  and, hence, the perforations  22 , chop-off cuts  24 , or other lines of termination  16  imparted by the rotatable blade  32 . The difference in position between the indicia  14  and lines of termination  16  is determined by a signal comparator  50 . This difference constitutes a position error signal. If the difference exceeds in either direction a pre-set limit, correction is made preferably based upon the position error signal. 
   Correction may be made by adjusting the angular velocity of a draw correction motor, the sheet length correction motor  40 , the rotatable blade  32 , or the rotatable print cylinder  28 . Preferably, the correction is made by adjusting the angular velocity of the sheet length correction motor  40 . The sheet length correction motor  40  and the draw motor can control the angular velocity of the rotatable blade  32  which imparts the perforations  21 , chop-off cuts  24 , or other lines of termination  16 , as well as the chop-off roll  36  and bedroll  38 , as well as the functions downstream of the apparatus  10 . In a preferred embodiment, the correction is preferably done by adjusting the angular velocity of the rotatable blade  32  relative to the velocity of the sheet  12 . The angular velocity is increased or decreased, as required, until the error signal comes within a desired limit or is equal to zero. 
   It should be readily recognized by one of skill in the art that several sheets  12 , according to the present invention, may be made in parallel by using multiple roll positions, as is known in the art. In such a process, a single web material having a width several times greater than the sheet  12  presented to the consumer as transported through the apparatus  10 . As used herein, a “web” comprises a plurality of sheets  12  integral with one another and simultaneously transported through the apparatus  10  parallel to the cross-machine direction. The web can be later slit or cut in the machine direction into individual sheets. Trim may also be removed from the longitudinal edges  26  of the web, as discussed above, with respect to single sheet widths. 
   Additionally, multiple indicia  14  and multiple lines of termination  16  may be imparted to the sheet  12  in parallel across the width of the web. The web may be later slit or cut into individual sheets, as required. However, it should be recognized by one of skill in the art that in such an embodiment the means used for sensing the angular position of print cylinder  28  should be provided in a spaced relationship in the cross-machine direction. If desired, one may add a plurality of additional means for sensing the angular position of print cylinder  28  (such as proximity switch  44 ) as indicia  14  are applied to sheet  12  at intermediate positions across the width of the web. 
   It should also be readily recognized by one of skill in the art that it may be desired to adjust the cross-machine direction registration of the web. Misregistration of the web material in the cross-machine direction can cause skew in the aforementioned spaced relationship. Compensation for such skew can be provided by adjusting the path length of the web using techniques known to those of skill in the art. Such techniques may include the use of bowed rolls, curved axis rolls having fixed and variable radii or curvature, cocking rolls, Mount Hope rolls, and the like. Such devices may be used to change the path length of one portion of the web or even an individual sheet  12  relative to the balance of the web or sheet  12 . 
   All documents cited in the Detailed Description of the Invention are, in relevant part, incorporated herein by reference; the citation of any document is not to be construed as an admission that it is prior art with respect to the present invention. To the extent that any meaning or definition of a term in this written document conflicts with any meaning or definition of the term in a document incorporated by reference, the meaning or definition assigned to the term in this written document shall govern. 
   Any dimensions and/or numerical values disclosed herein are not to be understood as being strictly limited to the exact dimension and/or numerical value recited. Instead, unless otherwise specified, each such dimension and/or numerical value is intended to mean both the recited dimension and/or numerical value and a functionally equivalent range surrounding that dimension and/or numerical value. For example, a dimension disclosed as “40 mm” is intended to mean “about 40 mm.” 
   While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. It is therefore intended to cover in the appended claims all such changes and modifications that are within the scope of this invention.