Patent Publication Number: US-2012031251-A1

Title: Paperboard sheet slitter-scorer apparatus and control method for correcting the positions of slitter knives and scorers thereof

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a cardboard sheet slitter-scorer apparatus and control method for correcting the positions of slitter knives and scorers thereof, and more particularly to a paperboard sheet slitter-scorer apparatus in which a plurality of slitters are placed in the width direction. 
     2. Description of the Related Art 
     Known conventional slitter-scorer apparatuses include those in which a slitter knife is positioned in a predetermined position in the width direction, in accordance with the number of manufactured sheets, to perform cutting work (e. g., Japanese Patent Publication No. 3717167). 
     Japanese Patent Examined Publication No. 1-014017 discloses a tool positioning method whereby multiple tools are transferred from a standby area to a setting area and positioned at a predetermined position on a sheet within the setting area using as a reference the position of an origin point between the standby area and the setting area. 
     Here, in a slitter-scorer apparatus such as that disclosed in Japanese Patent Publication No. 3717167 above, the above-described “predetermined position” is defined by assuming there are no dimensional changes associated with shearing or the like of the paperboard sheet caused by the cutting work of the slitter knife. However, it normally occurs that sheets are sheared due to factors such as slitter knife thickness, reducing the width-direction dimension of sheets after paperboard sheet splitting (after slitting) to smaller than the desired sheet dimension. 
     For example, using “d” as the amount of dimensional change caused by shearing, etc. of paperboard sheets by slitter knives, and “L” as the desired sheet width dimension, when two paperboard sheets are manufactured, the paperboard sheets are respectively sheared by slitter knives SN 6 , SN 0 , and SN 5 , as shown in  FIG. 9(   a ), and the respective sheet width dimensions after cutting become “L-d,” which is smaller than the desired width dimension L; when three paperboard sheets are manufactured, the paperboard sheets are respectively sheared by slitter knives SN 6 , SN 2 , SN 1 , and SN 5 , as shown in  FIG. 9(   b ), and the respective sheet width dimensions after cutting become “L-d,” which is smaller than the desired width dimension L. 
     The initial position of the slitter knives is therefore conventionally adjusted after installation of the slitter-scorer apparatus by loading all of the slitter knives in the slitter knife positions at which it is assumed there would be no dimensional change, then running sheets through the machine (initial adjustment production) so that the desired sheet width could be obtained. Specifically, an operator measured the width of sheets obtained when sheets are actually run through the machine, adjusting the position of the slitter knives to correct for the missing part of the desired sheet width. Repeated operations are also required to actually run sheets through the machine and measure the sheets obtained to confirm whether the desired sheet width had been obtained at that adjusted slitter knife position. This presented the problem that significant time and labor are required for such adjustment and operations by operators. 
     The present invention is therefore undertaken to resolve problems with the conventional art, and has the object of providing a slitter-scorer apparatus and position correction control method for the slitter knife and scorer thereof capable of effectively positioning slitter knives in the width direction so as to obtain paperboard sheets of a desired sheet width. 
     SUMMARY OF THE INVENTION 
     In order to achieve this object, the present invention provides a slitter scorer apparatus for cutting a paperboard sheet continuously supplied along a supply line and scoring the surface thereof, comprising: a plurality of scorers, parallely arrayed in the width direction relative to the paperboard sheet supply direction, for scoring the surface of the paperboard sheet; a plurality of slitters parallely arrayed in the width direction relative to the paperboard sheet supply direction, having slitter knives for cutting the paperboard sheet; a scorer width-direction moving means for independently moving each of the plurality of scorers in the width direction of the paperboard sheet; a slitter width-direction moving means for independently moving each of the plurality of slitters in the width direction of the paperboard sheet; and a control means for selecting a utilized slitter from among the plurality of slitters based on a production order, calculating the slitter knives of the selected slitter a width-direction positional correction amount relative to an initial position matched to the desired paperboard sheet dimension in the width direction in accordance with the amount of shearing by the slitter knives, and controlling the slitter width-direction moving means to position the slitter knives at a position based on that calculated correction amount. 
     According to the present invention thus constituted, for the slitter knives in the utilized slitter, the amount of positional correction in the width direction is calculated according to the amount of shearing by the slitter knives relative to an initial position, together with the desired width dimension of the paperboard sheet; the slitter knives are positioned at positions based on this calculated correction amount, thereby enabling effective positioning of the slitter knives in the width direction so that a desired sheet width can be obtained. As a result, a major reduction of time and labor can be achieved for initial adjustments during machine installation. 
     Preferably, in the present invention, the control means controls a scorer width-direction moving means by selecting a utilized scorer from among the plurality of scorers based on a production order, calculating a scorer correction amount relative to an initial position matched to the desired paperboard sheet scoring position according to the above-described slitter knife width-direction positional correction amount, and positioning the scorer at a position based on that calculated correction amount. 
     According to the present invention thus constituted, positioning of scorers in the width dimension can be effectively performed. As a result, a major reduction of time and sheet loss can be achieved for initial adjustments at the time of machine installation. 
     Preferably, in the present invention, the control device calculates, sequentially from one side in the width dimension of the slitter-scorer apparatus, a first utilized scorer correction amount, and calculates, sequentially from the other width dimension side of the slitter-scorer apparatus, a second utilized scorer correction amount, then corrects those calculated first and second correction amounts to match the utilized scorer and slitter to the mechanical center, thereby calculating a slitter knife width direction position correction amount and scorer correction amount based on the amount of shearing by the slitter knives. 
     According to the present invention thus constituted, positional control of slitter knives and scorers can be achieved by a simple control. Also, because the first and second correction amounts are corrected so as to place the utilized scorers and slitter knives based on the mechanical center, it becomes possible to position a slitter knife positioned at the furthest edge on one side of the width direction and a slitter knife positioned at the furthest edge on the other side of the width direction symmetrically about the mechanical center, thereby achieving a uniform width dimension for the trim cut off by the respective slitter knives. The paperboard sheets cut at the outermost side can therefore be prevented from becoming rejected sheets due to loss of trim on one side in the narrow width when a difference occurs between the width dimensions of the trim on the two sides during manufacturing. 
     Preferably, in the present invention, the control means controls a slitter width-direction moving means and scorer width-direction moving means so as to simultaneously position the utilized slitter knives and utilized scorers. 
     Preferably, in the present invention, further comprising a warpage amount detection sensor for detecting the amount of paperboard sheet warpage; the control means further corrects the slitter knife shearing amount-based slitter knife width direction positional correction amount according to the amount of paperboard sheet warpage detected by the warpage amount detection sensor. 
     According to the present invention thus constituted, paperboard sheet of a desired sheet width can be obtained with higher accuracy. 
     In order to achieve the above object, the present invention provides a method for controlling the positional correction of slitter knives and scorers in a slitter scorer apparatus, comprising: a plurality of slitters having slitter knives for cutting a sheet parallely arrayed so as to be independently movable in the width direction relative to the direction of supply of the paperboard sheet; and a plurality of scorers for scoring the surface of a sheet parallely arrayed so as to be independently movable in the width direction relative to the direction of supply of the paperboard sheet: said method comprising the steps of: selecting the utilized slitter and scorer from among the plurality of slitters and scorers based a production order; calculating a first correction amount for each of the utilized scorers based on the amount of shearing by the slitter knives sequentially from one side in the width direction of the slitter scorer apparatus; calculating a second correction amount for each of the utilized slitter knives based on the amount of shearing by the slitter knives sequentially from the other side in the width direction of the slitter scorer apparatus; correcting the calculated first and second correction amounts to align the utilized scorers and slitter knives to the mechanical center, and calculating slitter knife and scorer correction amounts relative to an initial position based on the desired dimension in the paperboard sheet width direction; and positioning the utilized slitters and scorers at a position based on that calculated correction amounts. 
     According to the present invention thus constituted, a slitter knife and scorer correction amounts are calculated relative to an initial position based on the desired paperboard sheet dimension in the width direction for the slitter knife of the utilized slitter; since the slitter and scorer are positioned at a position based on this calculated correction amount, it is possible to position the slitter knife effectively in the width direction so as to obtain a desired sheet width; it is also possible to effectively position the scorer in a desired scoring position. As a result, a major reduction in time and labor can be achieved when making initial adjustments at the time of machine installation. Also, because the first and second correction amounts are corrected so as to place the utilized scorers and slitter knives based on the mechanical center, it becomes possible to position a slitter knife positioned at the furthest edge on one side of the width direction and a slitter knife positioned at the furthest edge on the other side of the width direction symmetrically about the mechanical center, thereby achieving a uniform width dimension for the trim cut off by the respective slitter knives. Therefore the width dimension of trims cut by the respective slitter knives are respectively uniform, such that serpentine motion by the paperboard sheet in the supply direction during manufacturing can be prevented. 
     The present invention enables effective positioning of slitter knives in the width direction so that paperboard sheets of a desired sheet width can be obtained. Positioning of scorers can also be effectively performed in the width direction to perform scoring work at desired positions on the paperboard sheet. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1 : An overview side elevation of a slitter-scorer apparatus according to an embodiment of the present invention. 
         FIG. 2 : An overview front elevation of a slitter-scorer apparatus according to an embodiment of the present invention. 
         FIG. 3 : A figure viewed from the circumferential side of a slitter knife showing an example of a slitter knife used in a slitter-scorer apparatus according to an embodiment of the present invention. 
         FIG. 4 : A block diagram showing the overview structure of a slitter-scorer apparatus according to an embodiment of the present invention. 
         FIG. 5 : A flowchart showing position correction control in the width direction of the scorer and the slitter of a slitter-score apparatus according to an embodiment of the present invention. 
         FIG. 6 : A plan view schematically showing the position of a slitter and a scorer positioned by position correction control according to an embodiment of the present invention for three paperboard sheets manufacturing ( FIG. 6(   a )) and for four paperboard sheets manufacturing ( FIG. 6(   b )). 
         FIG. 7 : A diagram similar to  FIG. 3 , in which the state of the slitter knife after wear or after grinding is shown by a dot and dash line. 
         FIG. 8 : A diagram seen from the sheet supply direction showing a laser sensor for measuring the amount of warpage in the paperboard sheet, and the state of the paperboard sheet warpage. 
         FIG. 9 : A top view schematically showing a slitter position and paperboard sheet for the purpose of explaining the amount of shearing of the paperboard sheet by a slitter knife and the sheet width associated with that shearing. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION 
     Next, referring to the attached drawings, a slitter-scorer apparatus according to an embodiment of the present invention will be described. First, referring to  FIGS. 1 through 3 , the basic structure of a slitter-scorer apparatus according to an embodiment of the present invention will be described.  FIG. 1  is an overview side elevation showing a summary of a slitter-scorer apparatus according to an embodiment of the present invention;  FIG. 2  is an overview front elevation showing a summary of a slitter-scorer apparatus according to an embodiment of the present invention;  FIG. 3  is a front elevation showing an example of a slitter knife used in a slitter-scorer apparatus according to an embodiment of the present invention. 
     As shown in  FIG. 1 , Reference Numeral  1  indicates a slitter-scorer apparatus according to the present embodiment. This slitter-scorer apparatus  1  is provided on a paperboard sheet supply line at the dry end of a corrugator; a single facer, double facer, or the like (not shown) are placed on the upstream side thereof. The paperboard sheet S is supplied from this single facer or the like to a slitter-scorer apparatus  1 .  FIG. 1  shows the supply direction FW thereof. A cutter, stacker, or the like (not shown) are placed downstream of the corrugator. The paperboard sheet S is arranged to be transported by a suction conveyor (not shown). Note that the slitter-scorer apparatus  1  has a control device  200 , as explained below in  FIG. 4 . Below, the constitution of a mechanical main unit  180  in the apparatus  1  will be described. 
     The slitter-scorer apparatus  1  according to the present embodiment comprises an upstream scorer  2  arrayed along the supply direction FW, a downstream scorer  4 , and a slitter  6  arrayed on the downstream side of 4. 
     First, referring to  FIG. 1 , the constitution of the upstream scorer  2  and the downstream scorer  4  will be described. 
     As shown in  FIG. 1 , the upstream scorer  2  has an upper scoring roll  8  and a lower scoring roll  10 ; a plurality of groups of these rolls  8  and  10  are placed in the width direction of the slitter-scorer apparatus  1 . 
     A raised portion continuous in the circumferential direction thereof is formed at approximately the center of the circumferential surface of the upper scoring roll  8 , while an indented portion continuous in the circumferential direction thereof is formed at approximately the center of the circumferential surface of the lower scoring roll  10 . The bottom surface of the paperboard sheet S is guided by a guide  11 ; the circumferential surface of the lower scoring roll  10  is disposed at a position such as that shown in  FIG. 1  to match the bottom surface of the supplied paperboard sheet S, and is supported by a yoke  12 , described below, so as to be unable to move in the up/down direction of the apparatus  1 . 
     At the same time, the upper scoring roll  8  is linked to a pivoting lever  16  capable of pivoting about a rotating drive shaft  14 , described below. This pivoting lever  16  is arranged to pivot by the action of an air cylinder  20  linked to a yoke  18 ; with this pivoting, the upper scoring roll  8  is able to move to a scoring position such as that shown by the dot and dash line in  FIG. 1 , and to a standby position such as that shown by the solid line in  FIG. 1 . 
     Similar to the upstream scorer  2 , the downstream scorer  4  also has an upper scoring roll  22  and a lower scoring roll  24 . Similar to the upstream scorer  6 , the lower scoring roll  24  is supported by a yoke  26  so as to be unable to move in the up/down direction of the apparatus  1 . Similar to the upstream-side scorer  6 , the upper scoring roll  22  is arranged to be movable to a position at which scoring is implemented and to a standby position by an air cylinder  34  linked to a pivoting bar  30  capable of pivoting about a rotating drive shaft  28  (described below) and a yoke  32 . 
     Rotating drive shafts  14  and  28  are respectively erected on each frame  36  and  38  at both sides in the width direction of apparatus  1  (see  FIG. 2 ), and extend in the width direction. Each of the rotating drive shafts  14  and  28  is respectively linked via a power transmission mechanism having a timing belt and a gear mechanism to a rotating drive motor  40  (see  FIG. 2 ), and linked via a timing belt and a pulley to each of the upper scoring rolls  8  and  22 . Each upper scoring roll  8  and  22  rotates clockwise in  FIG. 1  under the rotation of this rotating drive motor  40 . 
     At the same time rotating drive shafts  42  and  44 , erected on each frame  36  and  38  (see  FIG. 2 ) and extending in the width direction, are similarly provided on lower scoring rolls  10  and  24 , respectively. These rotating drive shafts  42  and  44  are linked to the rotating drive motor  40  (see  FIG. 2 ), and each upper scoring roll  22  and  24  is rotated counterclockwise in  FIG. 1  by the rotation of the rotating drive motor  40 . 
     Next, a structure for respectively moving the upper scoring rolls  8  and  10 , of which plurality of sets are placed in the width direction in the upstream scorer  2  will be described. 
     Guides  50  and  56 , installed on each of the frames  36  and  38  (see  FIG. 2 ) and extending in the width direction, and threaded shafts  52  and  58 , installed on each of the frames  36  and  38  (see  FIG. 2 ) and extending in the width direction, are respectively placed on the upper and lower parts of the machine  1  in order to respectively move the plurality of upper scoring rolls  8  and  10  independently in the width direction of the machine  1 . Each of these threaded shafts  52  and  58  are placed so as to penetrate each yoke  18  and  12 . Each yoke  18  and  12  is provided with guide members  53  and  59 , which slide with guide units  50  and  56  so as to be guided in the width direction along the guide units  50  and  56 . 
     Width direction positioning motors  54  and  60  are respectively placed on the yokes  18  and  12 . The output shafts of these motors  54  and  60  are linked to rotors, which have a threaded engagement with the above-described threaded shafts  52  and  58 ; each yoke  18  and  12  is constituted to respectively move independently in the width direction along the guides  50  and  56  by rotating each rotating unit through the rotational drive supplied by each motor  54  and  60 . 
     Next, the upper scoring rolls  22  and  24  in the downstream scorer  4  are also respectively moved in the width direction by the same type of structure as that found in the upstream scorer  2 . That is, the yokes  32  and  26  are respectively constituted to be moved independently in the width direction along the guide units  50  and  56  by the screw shafts  62  and  64 , the guide members  66  and  68 , the width direction positioning motors  70  and  72 , and the rotating units which thread-engage the threaded shafts  62  and  64 . 
     The plurality of sets of upper and lower scoring rolls are selectively operated and positioned in the width direction according to each order such as the number of paperboard sheets manufactured, the number of scores, and slit forming width. 
     Next, referring to  FIGS. 1 through 3 , the constitution of the slitter  6  will be described. 
     The slitter  6  has a slitter knife  80  and a slitter knife receiving member  82 . 
     As shown in  FIG. 3(   a ), the slitter knife  80  is a disk-shaped rotating knife, of a thin profile throughout, with a blade thickness of approximately 1 mm and a predetermined taper angle in the direction of the blade edge. As shown in  FIG. 3(   b ), a predetermined very small angle is imparted to the blade edge at the circumference thereof. 
     A channel, continuous in the circumferential direction, is formed at approximately the center portion of the circumferential surface of the slitter knife receiving member  82 . As will be described below, the slitter knife  80  is constituted to move up and down, and the blade edge of the slitter knife  80  penetrates and engages the channel in the slitter knife receiving member  82 , thereby slitting (cutting) the paperboard sheet S. The bottom surface of the sheet S is guided by the guide  83 . 
     The slitter knife receiving member  82  is disposed at a position such as that shown in  FIG. 1  so that its circumferential surface matches the top surface of the supplied paperboard sheet S, and is supported by a yoke  84 , described below, so as to be unable to move in the up and down direction of the apparatus  1 . 
     At the same time, the slitter knife  80  is linked to a pivoting lever  88  capable of pivoting about a rotational drive shaft  86 , described below. This pivoting lever  88  is arranged to pivot by the action of an air cylinder  92  linked to a yoke  90 ; in connection with this pivoting, the slitter knife  80  is able to move to a slitting position such as that shown by the dot and dash line in  FIG. 1 , and to a standby position such as that shown by the solid line in  FIG. 1 . 
     The rotational drive shaft  86 , as shown in  FIG. 2 , is installed on each of the frames  36  and  38  on the apparatus  1 , and extends in the width direction. This rotational drive shaft  86  is linked to the rotating drive motor  40  shown in  FIG. 2  via a power transmission mechanism having a timing belt and a gear mechanism, and is linked to the slitter knife  80  via a transmission belt and a pulley. The slitter knife  80  rotates counterclockwise in  FIG. 1  by the rotation of this rotating drive motor  40 . 
     On the slitter knife receiving member  82  side, as well, a rotational drive shaft  94  installed on each frame  36  and  38  (see  FIG. 2 ) and extending in the width direction, is provided so as to penetrate the bottom end portion of the yoke  84 . The slitter knife receiving member  82  is linked to this rotational drive shaft  94  via a transmission belt and pulley. In the same manner as described above for the rotational drive shaft  86 , the rotational drive shaft  94  is also linked to the rotating drive motor  40 . The slitter knife receiving member  82  rotates clockwise in  FIG. 1  by the rotation of this rotating drive motor  40 . 
     Note that in this embodiment, as shown in  FIG. 2 , seven sets of the slitter knife  80  and the slitter knife receiving member  82  are placed in the width direction of the apparatus  1 , but in the structure described above each of the sets is shared. 
     Next, a structure for respectively moving the slitter knife  80  and the slitter knife receiving member  82 , of which plurality of sets are provided, in the width direction will be described. 
     As shown in  FIG. 2 , guide units  100  and  102  installed on frames  36  and  38  and extending in the width direction, and threaded shafts  104  and  106  installed on the frames  36  and  38  and extending in the width direction, are respectively placed on the upper part and the lower part of the apparatus  1  to independently move the plurality of slitter knife  80  and slitter knife receiving member  82  sets in the width direction of the apparatus  1 . Each of these threaded shafts  104  and  106  are placed so as to penetrate each yoke  90  and  84 . Each yoke  90  and  94  is provided with guide members  108  and  110 , which slide with guide units  100  and  106  so as to be guided in the width direction along the guide units  100  and  106 . 
     Width direction positioning motors  112  and  114  are respectively placed on the yokes  90  and  84 . The output shafts of these motors  112  and  114  are linked to the rotating units which engage the above-described threaded shafts  104  and  106 . By rotating each of the rotating units using the rotational drive of the motors  112  and  114 , the yoke  90  and  94  is constituted to move independently in along the guide units  100  and  102  in the width direction. 
     The plurality of slitter knives  80  and slitter knife receiving members  82  are selectively operated and positioned in the width direction according to each order such as the number of manufactured sheets, number of scores, and slit forming width. 
     As shown in  FIG. 4 , the slitter-scorer apparatus  1  has a control device  200  connected to the mechanical main unit  180  ( FIG. 1  and  FIG. 2 ) of the apparatus  1 ; this control device  200  controls the operation of the upstream scorer  2 , the downstream scorer  4 , and the upstream scorer  6  described above. The control device  200  is connected to a production management device  220 . 
     Below, referring to  FIG. 5 , positioning correction control in the width direction of a slitter and scorer using the slitter-scorer apparatus  1  control device  200  according to the present embodiment will be described. 
       FIG. 5  is a flowchart showing position correction control in the width direction of the scorer and the slitter of the slitter-score apparatus according to an embodiment of the present invention. In  FIG. 5 , steps are denoted by “S.” 
     In the control shown in  FIG. 5 , a scorer correction position is calculated in S 3  through S 9 ; a slitter correction position is calculated in S 10  through S 12 , and the corrected positions are modified in S 13  and S 14  so that the scorer and slitter at those calculated corrected positions are symmetrically disposed relative to the mechanical center of the apparatus  1  or to the paperboard sheet in the width direction thereof. 
     First, in S 1 , production command data input to the production management device  220 ; this is where width dimension of a base paper (sheet width of the paperboard sheet), number of sheets manufactured (three sheets, four sheets, etc.), slit width (slitter spacing prior to compensation control), scoring position dimension (scoring position prior to correction control), scoring pressure, paperboard sheet fluting, and the like are input. 
     In S 1 , the shaft is apportioned according to the input sheet width and number of sheets manufactured. I.e., a determination is made as to which of the plurality of slitters  6  and scorers  2  and  4  to use according to the sheet width and number of sheets manufactured. A in-use flag is raised relative to the slitter  6  and scorer  2 ,  4  determined for use. For example, if the number of sheets manufactured is three, in-use flags are raised for four slitters. 
     Next, in S 2 , a correction counter C (C=1) is set for the slitters and scorers for which a in-use flag is raised in S 1 . 
     Next, in S 3 , counting up from the apparatus  1  drive side (the side on which the motor  40  and frame  36  shown in  FIG. 2  are placed), the values for positioning the counter C for the slitter on which the in-use flag is raised, and the C+1 numbered yokes  84  and  90  for the slitter on which the in-use flag is raised (the slitter for which the in-use flag is raised relative to the counter C slitter on the apparatus  1  operating side (the side of the frame  38  on the opposite side to that on which the motor  40  is placed) are set to L(C) and L(C)+1). L(C) and L(C+1) are the initial positions (pre-correction positions) calculated from the base paper width dimension, the number of manufactured paperboard sheets, and the slit width input in S 1 . 
     Next, in S 4 , a scoring correction coefficient Cv is set by the following equation: 
         Cv =( C+ 1)× d+ ½ d    Eq. (1)
 
     “d” is the amount of shearing of the paperboard sheet by the slitter knife; here it is obtained from experience, experimentation, etc., and a pre-input value is used. For example, with a slitter knife such as that shown in  FIG. 3 , the amount of shearing from the circumferential portion thereof is 0.1 mm. 
     Next, in S 5 , for the scorers for which an in-use flag is raised in S 1 , those for which the positioning value (the positional dimension of the score input in S 1 ) are within the width direction range of the L(C) and L(C+1) set in S 3  have a positioning value LS(C) which is set by the following equation: 
         LS ( C ) =“the current positioning value (scoring positional dimension of the input in  S 1)”+ Cv    Eq. (2).
 
     Next, in S 6 , the counter C is incremented by 1, and advancing to S 7 . 
     In S 7 , when the in-use flag is raised for the C+1 numbered slitter, counting from the drive side, returning to S 3 , and steps S 3  through S 7  are repeated. In S 7 , when the in-use flag is not raised for the C+1 numbered slitter, as counted from the drive side, advancing to S 8 . 
     For example, when the number of paperboard sheets manufactured is three, each process in S 3  through S 6  is repeated; when the counter C reaches 4, “counter C+1=5” occurs at S 7 , and since there is no slitter used on the remaining operating side (there is no slitter for which the in-use flag is raised), advancing to S 8 . 
     Next, in S 8 , the value of counter C is stored in Z. 
     Next, in S 9 , the corrected position ZL for a slitter for which the in-use flag has been raised and which is closest to the operating side is stored using the following equation: 
         ZL=L ( C ) P+d× ( C− 1)   Eq. (3)
 
     In S 9 , if the number of manufactured sheets is three, for example, the counter C is at  4  in S 9 , and the corrected position ZL for a slitter positioned furthest to the operating side for which an in-use flag is raised is set to a value obtained by adding the correction amount “shear amount d×(C−1)” to the initial position L ( 4 ) set in S 3 . 
     Next, in S 10 , the positioning value L′(C) of the post-correction C numbered slitter as counted from the drive side is set by the following equation: 
         L ′( C )= L ( C )+ d ×( C− 1)   Eq. (4)
 
     In other words, a value obtained by adding the correction amount “shear amount d×(C−1)” to the initial position L(C) set in S 3  is set as the post-correction positioning value L′(C). 
     Note that at the stage of first transitioning from S 9  to this S 10  processing, the C-numbered slitter as counted from the drive side is, for example, at C=4 for three sheets manufacturing, thus becoming the slitter positioned furthest to the operating side for which the in-use flag is raised. 
     Next, in S 11 , the value of the correction counter is decremented by C=C−1. 
     Next, in S 12 , a determination is made as to whether C=1; if C is determined to equal  1 , processing steps S 10  through S 12  are repeated. The post-correction positioning values L′(C) in S 10  are thus respectively set in order from the slitter positioned furthest to the operating side for which the in-use flag is set, up to the slitter positioned furthest to the drive side for which the in-use flag is set. 
     Next, in S 12 , when a determination is made that C=1, advancing to S 13 , and a correction amount Sh for matching each slitter and scorer to the mechanical center of the apparatus  1  is calculated. In other words, in the control shown in  FIG. 5  the amount of correction of each slitter and scorer is calculated sequentially from the drive side, therefore each slitter and each scorer is shifted toward the operating side of the apparatus  1 , and a correction amount Sh for returning these to the mechanical center is sought in S 13 . 
     The correction amount Sh is expressed by the following expression using: the correction position ZL of the slitter positioned furthest to the operating side and stored in S 9 , the initial position L( 1 ) of the slitter positioned furthest to the drive side, and the position L(Z) of the slitter positioned furthest to the operating side and stored in S 8 . 
         Sh =(( ZL−L (1))−( L ( Z )− L (1))/2   Eq. (5)
 
     Next, in S 14 , the value Sh is subtracted from each of the post-correction positioning values for all slitters  6  and scorers  2  and  4  for which in-use flags are raised (yokes  84 ,  90 ,  15 ,  12 ,  32 ,  26 ), which is to say from the LS(C) obtained in S 5  and the L′(C) obtained in S 10 . I.e., the final corrected position L″(C) for each slitter on which an in-use flag is raised and the final corrected position of each scorer LS′(C) on which an in-use flag is raised is given by the following expression. 
         L ″( C )= L ( C )+ d ×( C− 1)− Sh    Eq. (6)
 
         LS ′( C )= LS ( C )=“score position dimension of the input in  S 1″+Cv−Sh   Eq. (7)
 
     The slitter positioned furthest to the drive side with for which an in-use flag is raised and the scorer positioned furthest to the operating side for which an in-use flag is raised are thus in a symmetrical position relative to the mechanical center, and by making the width of the paperboard sheet trim (see  FIG. 6 ) equal on the drive side and the operating side, serpentine motion of the sheet is avoided during manufacturing. 
     Next, in S 15 , all the slitter  6  and the yokes  84 ,  90 ,  18 ,  12 ,  32 , and  26  for which in-use flags are in use are positioned at their respective post-correction positioning values L″(C) and LS′(C). 
     Next, referring to  FIG. 6 , the content of the positioning correction control shown in  FIG. 5  will be described schematically. 
       FIG. 6  is plan view schematically showing the position of a slitter and a scorer positioned by position correction control according to an embodiment of the present invention for three paperboard sheets manufacturing ( FIG. 6(   a )) and four paperboard sheets manufacturing ( FIG. 6(   b )). 
     Note that in  FIG. 6 , the symbol SN represents a slitter knife; SC represents each of the scoring rolls in the scorer; A shows the slitter knife position determined on the assumption that no dimensional change due to shearing or the like of the paperboard sheet by the slitter knives will occur; Ash shows the slitter knife position after executing positional correction control according to an embodiment of the present invention; d shows the amount of shearing of the paperboard sheet by the slitter knives. 
     First, as shown in  FIG. 6(   a ), when manufacturing three paperboard sheets, the slitter knives SN 1  and SN 2  on the center side of the paperboard sheet S are both positioned by the positioning correction control discussed above and shown in  FIG. 5 , from a position A at which there is assumed to be no shear amount, to the position Ash located on the outer side in the width direction by a correction amount of d/2. In the three paperboard sheets manufacturing case, there is no slitter at the center of the sheet, and the amount of correction to the scorers SC 0  and SC 1  between the slitters SN 1  and SN 2  on the center side of the sheet S is zero. 
     At the same time, the scorers SC 3 , SC 4 , SC 6 , and SC 7  are each positioned on the outer side in the width direction by the same correction amount as the correction amount toward the outer side in the width direction to the slitter knives SN 1  and SN 2 . 
     The slitter knife SN 6  furthest to the drive side and the slitter knife SN 5  furthest to the operating side are respectively positioned at the Ash position toward the outside in the width direction by a correction amount of 3d/2 from the position A at which there is assumed to be no shear. 
     These correction amounts d/2 and 3d/2 are basically the sum of the sheet shearing amount from the center cross section in the width direction of the slitter knife used to obtain the correction amount (the section through which Ash passes in  FIG. 6 ) to the center of the sheet. 
     By positioning these slitter knives SN 0  through SN 6 , as shown in  FIG. 6(   a ), the dimension in the width direction of the paperboard sheet S after cutting have the same dimension L as the desired width dimension L. 
     Next, as shown in  FIG. 6(   b ), when manufacturing four paperboard sheets, the slitter knife SN  0  at the center of the paperboard sheet S is left at its initial position and the slitter knives SN 1  and SN 2  on both sides thereof are positioned by the positioning correction control discussed above and shown in  FIG. 5 , from a position A at which there is assumed to be no shear amount, to the position Ash located on the outer side in the width direction by a correction amount of d. 
     At the same time, the scorers SC 1  and SC 2  or SC 0  and SC 6  between the slitter knives SN 0  and SN 1  or SN 2  at the center of the sheet are all positioned on the outside in the width direction by a correction amount d/2. This is to also position the scorers SC 1 , SC 2 , SC 0 , and SC 6 , which also are positioned to the outer side in the width direction by a correction amount d/2, which is the d/2 sheared amount on one side of the slitter knife SN 0  at the center of the sheet. 
     Also, the slitter knife SN 6  furthest to the drive side and the slitter knife SN 5  furthest to the operating side are respectively both positioned at the Ash position toward the outside in the width direction by a correction amount 2d from the position A at which it is assumed there is no shear. 
     The scorers SC 3  and SC 4  between the slitter knives SN 1  and SN 5 , and the scorers SC 7  and SN 8  between the slitter knives SN 2  and SN 6  are each positioned to the outer side in the width direction by the same correction amount as the amount of correction to the slitter knives SN 1  and SN 2  toward the outer side in the width direction. 
     In the four paperboard sheets manufacturing case, as well, the correction amounts d and 2d to each of the slitter knives SN 1 , SN 2 , SN 5 , and SN 6  are basically the sum of the sheet shearing amount from the center cross section in the width direction of the slitter knife used to obtain the correction amount (the section through which Ash passes in  FIG. 6 ) to the center of the sheet. 
     By positioning these slitter knives SN 0  through SN 6 , as shown in  FIG. 6(   b ), the dimension in the width direction of the paperboard sheet S after cutting have the same dimension L as the desired width dimension L. 
     Also, as shown in  FIGS. 6(   a ) and ( b ), the trim widths are mutually equal on the drive side and on the operating side. 
     According to the present embodiment described above, use of correction control based on a slitter knife shearing amount such as that shown in  FIG. 5  enables the slitter knives SN 0  through SN 6  to be, as shown for example in FIGS.  6 ( a ) and  6 ( b ) for the three paperboard sheets manufacturing and four paperboard sheets manufacturing cases, positioned at a position such that the dimension in the width direction of the paperboard sheet S after cutting is the same dimension L as the desired dimension L relative to an initial position (a position determined on the assumption that there is no dimensional change due to shearing caused by cutting). 
     Next, factors affecting the “paperboard sheet shear amount d caused by the slitter knives” will be described. In S 4  of  FIG. 5  of the present embodiment, a shearing amount d obtained in advance through experience, experimentation, or the like is used to find the above-described correction amounts L″(C) and LS′(C). 
     The inventors have found that the shear amount d is affected by parameters such as paperboard sheet paper quality, thickness, type, amount and shape of sheet warpage at time of sheet manufacture, sheet moisture content and temperature, and amount of slitter knife wear. 
     Among these, it also become apparent that the amount of slitter knife wear (amount of grinding) and the amount of paperboard sheet warpage greatly affect the amount of shearing. 
     As the blade edge is repeatedly worn or ground, as shown by the dot and dash line in  FIG. 7 , the amount of slitter knife wear (amount of grinding) affects the amount of shearing, since this wear or grinding leads to cutting the paperboard sheet with the thick portion of the blade. 
     Since the correction amount thus increases with the amount of wear or the amount of grinding of the slitter knife blade edge, when the blade edge wear amount or grinding amount is large (when there is significant wear or grinding), that blade edge wear amount or grinding amount can be added to the positioning control in  FIG. 5  in order to increase the above-described correction amount L″(C) and LS′(C) to enable further correction. 
     With respect to the amount of warpage of the paperboard sheet, flattening out a sheet which is slitted and scored in a warped state greatly affects the shearing amount d, since such flattening causes the positions of those slitting and scoring operations to move toward the outer sides relative to the center of the sheet. 
     Therefore the larger the amount of warpage, the more the above-described correction amounts L″(C) and LS′(C) may be reduced. 
     As shown in  FIG. 8 , for example, beam sensors  200  and  202  may be disposed on the upstream side of the slitter scorer apparatus  1 , and the amount of warpage of the paperboard sheet S detected by measuring the height at which a beam is occluded by the paperboard sheet, so that further correction can be made to increase the above-described correction amounts L″(C) and LS′(C). 
     The moisture content and temperature of the paperboard sheet can also be detected using a moisture sensor and temperature sensor and, in combination with sheet paper quality data, further correction can be made to reduce the correction amounts L″(C) and LS′(C) in accordance with the amount of shrinkage of the paperboard sheet. 
     Furthermore, the amount of correction to the slitter and scorer used may be calculated sequentially from the drive side or calculated sequentially from the operating side. 
     Although the present invention has been explained with reference to a specific, preferred embodiment, one of ordinary skilled in the art will recognize that modifications and improvements can be made while remaining within the spirit and scope of the invention. The scope of the invention is determined solely by the appended claims.