Patent Publication Number: US-2007117700-A1

Title: Filter rod making machine

Description:
TECHNICAL FIELD  
      This invention relates to a machine for making a filter rod which is a connected series of composite filters such as dual filters, for manufacturing filter cigarettes, and particularly a machine with double tracks for making filter rods.  
     BACKGROUND ART  
      A machine for making this type of filter rod is disclosed in Japanese Unexamined Patent Publication No. 2003-24035, for example. The making machine in this publication includes a conveyor for cylindrical filter elements, and two types of filter elements are fed onto the conveyor. The two types of filter elements are arranged alternately on the conveyor, along the direction of conveyor transportation, and transported in one direction by the conveyor. In the terminal region of the conveyor, adjacent filter elements come into close contact, thereby forming a composite element column, and the formed composite element column is fed from the conveyor to a wrapping apparatus. The wrapping apparatus wraps the composite element column in forming paper, thereby forming a composite element rod, and delivers the formed composite element rod to a cutting apparatus. The cutting apparatus cuts the composite element rod at specified intervals to form individual filter rods.  
      The filter rods are then fed to a machine for manufacturing filter cigarettes, namely a so-called filter attachment machine. The filter attachment machine cuts the filter rod into individual filter plugs, places a cigarette at each end of the filter plug, joins the filter plug and two cigarettes together by wrapping tip paper, thereby forming a double filter cigarette, and then cuts the double filter cigarette at the center of the filter plug, thereby forming individual filter cigarettes.  
      More specifically, the filter rod has an integer times the length of the filter plug, and the filter plug has twice the length of the filter contained in the filter cigarette. When the filter is a charcoal type dual filter, the filter plug comprises a plain filter element located in the center and two half charcoal-filter elements each adjacent to an end of the plain filter element. These half-elements are produced from cutting the composite element rod or the filter rod at the center of the charcoal filter element.  
      In order to improve the production capacity of the filter rod making machine, it is necessary to increase the traveling speed of the composite element column, or in other words, the traveling speed of the composite element rod. However, since the composite element column is formed by arranging different types of filter elements alternately on the conveyor as mentioned above, it is difficult to increase the speed of forming the composite element column, and therefore it is difficult to increase the traveling speed of the composite element rod as desired.  
      Meanwhile, when the above-mentioned conveyor is made as double conveyors which are arranged parallel to each other and a wrapping apparatus is provided downstream of each conveyor, two composite elements rods can be formed simultaneously. In this case, the production capacity of the making machine can be increased without increasing the speed of forming the composite element column (traveling speed of the composite element rod). In this case, it is preferable that the cutting apparatus be shared by both wrapping apparatuses, in which case the cutting apparatus cuts the composite element rods delivered from both wrapping apparatuses virtually at the same timing, thereby forming filter rods. When the cutting apparatus is shared by both wrapping apparatuses like this, an increase in complexity and size of the making machine can be avoided.  
      In the case of the making machine with the composite-element-rod forming track doubled as described above, if, on one of the twin forming tracks, the cutting for the filter rod, namely the cutting position at which the composite element rod is to be cut for forming a filter rod shifts, such shift cannot be compensated by adjusting the timing at which the cutting apparatus performs cutting. In other words, the adjustment of the cutting position for the filter rod on one of the two forming tracks causes a shift of the cutting position for the filter rod on the other forming track.  
     DISCLOSURE OF THE INVENTION  
      The primary object of this invention is to provide a filter rod making machine capable of adjusting the cutting position for the filter rod without changing the timing at which the cutting apparatus cuts the composite element rod.  
      In order to achieve this object, a filter rod making machine according to this invention comprises  
      a hopper apparatus for feeding different types of filter elements, the hopper apparatus including a plurality of hoppers each storing a large number of departing rods for forming the filter elements, and a plurality of element feeders for taking the departing rods out of the hoppers, one by one, forming the filter elements by cutting the taken-out departing rods, and transporting the formed filter elements at intervals,  
      an element conveyor for receiving the filter elements from the element feeders of the hopper apparatus and transporting the received filter elements in one direction while continuously forming the filter elements into an element stream in which the different types of filter elements are arranged in the direction of transportation in a specified order,  
      a wrapping apparatus for receiving the element stream from the element conveyor, forming the received element stream into a composite element column in which the filter elements are in close contact with each other, forming the composite element column into a composite element rod by continuously wrapping the composite element column in a paper web, and delivering the formed composite element rod,  
      a cutting apparatus disposed downstream of the wrapping apparatus in the direction in which the composite element rod is delivered, for cutting the composite element rod into filter rods of a specified length, the filter rod including, at each end, a half-element produced from cutting the filter element of the same type in two halves,  
      an inspection apparatus for detecting the length of the half-element in the formed filter rod and feeding detection information, and  
      a change apparatus disposed on a filter element, transportation path extending from each of the hoppers up to the wrapping apparatus, for changing the transportation phase of the composite element column on the basis of the detection information from the inspection apparatus.  
      In the filter rod making machine described above, the inspection apparatus detects, for example the length of the half-element at the leading end of the filter rod viewed in the direction in which the composite element rod is transported. When the detected length of the half-element is smaller than a specified value, the change apparatus delays the transportation phase of the composite element column. Meanwhile, when the detected length of the half-element is greater than a specified value, the change apparatus advances the transportation phase of the composite element column. Consequently, even if the length of the half-element of the filter rod comes out of a specified range, the length of the half-element of the filter rod is automatically brought back into the specified range in the subsequent filter-rod making process, without changing the timing at which the cutting apparatus cuts the composite element rod.  
      Specifically, the wrapping apparatus may include  
      an endless garniture tape arranged to travel in the direction in which the element stream is transported and make the individual filter elements of the element stream travel with the paper web,  
      a tongue arranged to allow passage of the paper web and the element stream, form the composite element column by exerting a braking force on the individual filter elements of the element stream when the paper web and the element stream pass across the tongue, and allow the formed composite element column to be transported in the direction in which the garniture tape travels, and  
      a brake means for further exerting a braking force on each of the filter elements forming the composite element column when the filter element is just leaving the tongue, thereby producing a specified space between the filter element that has left the tongue and the succeeding filter element, in the direction in which the composite element column is transported.  
      In this case, preferably, the wrapping apparatus further includes a rear tongue disposed downstream of the above-mentioned tongue in the direction in which the composite element column is transported and arranged to allow passage of the paper web and the composite element column, wherein the rear tongue further exerts a braking force on the individual filter elements of the composite element column when the paper web and the composite element column pass through the rear tongue, thereby bringing the filter elements into close contact with each other so that the spaces between the individual filter elements are removed.  
      Meanwhile, the element feeder may include a feed wheel rotatably arranged near the element conveyor, where the feed wheel has, on a circumferential surface thereof, a plurality of feed claws arranged at equal intervals in circumferential direction of the feed wheel so that the feed claws feed the individual filter elements onto the element conveyor at intervals.  
      In this case, the change apparatus can include a differential gear mechanism capable of changing a rotation phase of the feed wheel, and a step motor for operating the differential gear mechanism on the basis of the detection information from the inspection apparatus.  
      When the rotation phase of the feed wheel is changed by the change apparatus, the above-mentioned space is increased or decreased, so that a transportation phase of the composite element column is adjusted.  
      The making machine may further comprise a second element conveyor similar to the above-mentioned element conveyor. In this case, the wrapping apparatus forms composite element rods from the element streams fed by the element conveyors, respectively, and the cutting apparatus is used in common for cutting both composite element rods sent out from the wrapping apparatus.  
      In this making machine, since two composite element rods can be formed simultaneously, the capacity to produce the filter rods improves. Further, the transportation phases of the two composite element columns, each formed into a composite element rod, are changed independently. Thus, although used in common for cutting both composite element rods, the cutting apparatus can cut each composite element rod at correct positions.  
      The composite element column has, for example plain elements formed of a bundle of filter fiber wrapped in forming paper, and charcoal elements formed of a bundle of filter fiber containing activated charcoal particle wrapped in forming paper. In this case, the cutting apparatus cuts the composite element rod at the center of the charcoal element so that the filter rod has, at each end, a half-element produced from the charcoal element, where the half-element and the plain element are visually identifiable although covered with the paper web.  
      When the filter rod has the above-described formation, the inspection apparatus can include a camera for imaging the filter rod, and an inspection circuit for detecting the length of the half-element included in the filter rod from an image of the filter rod fed from the camera, where the inspection circuit can detect a boundary between the half-element and the plain element on the basis of a difference in density between the part of the image corresponding to the half-element and the part of the image corresponding to the plain element. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      [ FIG. 1 ] A diagram schematically showing an upstream section of an embodiment of a filter rod making machine.  
      [ FIG. 2 ] A side view schematically showing an element feeder for filter elements.  
      [ FIG. 3 ] A diagram for explaining how a departing rod is taken out of a take-out drum in the element feeder shown in  FIG. 2 .  
      [ FIG. 4 ] A diagram for explaining how a departing rod is separated into individual filter elements.  
      [ FIG. 5 ] A plan view of the element feeder shown in  FIG. 2 .  
      [ FIG. 6 ] A diagram schematically showing a downstream section of the filter rod making machine.  
      [ FIG. 7 ] A front view showing a wrapping apparatus in the downstream section.  
      [ FIG. 8 ] A diagram showing filter rods obtained by cutting a composite element rod, where (I) shows a non-defective filter rod while (II) and (III) show defective filter rods, respectively.  
      [ FIG. 9 ] A diagram showing a phase change apparatus partly sectioned.  
      [ FIG. 10 ] A diagram for explaining how the rotation phase of a feed wheel is converted into the transportation phase of a composite element column. 
    
    
     BEST MODE OF CARRYING OUT THE INVENTION  
       FIG. 1  shows an upstream section  10   U  of a double-track-type filter-rod making machine.  
      The upstream section  10   U  includes a hopper apparatus  12 , and the hopper apparatus  12  comprises, for example four hoppers  16   a  to  16   d . These hoppers  16  are arranged horizontally adjacent to each other and each store a large number of departing rods. Specifically, in  FIG. 1 , in the first and third hoppers  16   a  and  16   c  from the left are stored plain rods F A  as departing rods, while in the hoppers  16   b ,  16   d , charcoal rods F C  different from the plain rods F A  are stored as departing rods.  
      The plain rod F A  includes a bundle of acetate fiber and wrapping paper which is wrapped around the fiber bundle to form it into a rod-like shape. The charcoal rod F C  is obtained by including activated charcoal particles in the plain rod, where the activated charcoal particles are uniformly distributed in the fiber bundle.  
      The upstream section  10   U  further includes a front conveyor  18   f  and a rear conveyor  18   r , where the conveyors  18  are arranged parallel to the series of hoppers  16   a  to  16   d . The front conveyor  18   f  extends from the hopper  16   a  to the hopper  16   d , while the rear conveyor  18   r  is located between the front conveyor  18   b  and the series of hoppers  16  and extends from the hopper  16   a  to the hopper  16   b.    
      The front and rear conveyors  18   f ,  18   r  include endless suction belts  22   f ,  22   r , respectively. The suction belts  22   f ,  22   r  are each arranged to pass around a drive roller  24 . The drive rollers  24  are located at the terminal ends of the front and rear conveyors  18   f ,  18   r , respectively. As the drive rollers  24  are rotated, the suctions belts  22   f ,  22   r  travel in the same direction at the same speed. The front and rear conveyors  18   f ,  18   r  further include suction chambers (not shown) to supply specified suction pressure to the suction belts  22   f ,  22   r , respectively.  
      The hopper apparatus  12  further includes element feeders  26   a ,  26   b  for feeding plain rods F A  and charcoal rods F C  from the hoppers  16   a ,  16   b  to the rear conveyer  18   r , respectively, and element feeders  26   c ,  26   d  for feeding plain rods F A  and charcoal rods F C  from the hoppers  16   c ,  16   d  to the front conveyer  18   f , respectively. Also the element feeders  26   a  to  26   d  are arranged along the series of the hoppers  16   a  to  16   d.    
      The element feeders  26   a  to  26   d  have virtually the same structure. Thus, only the structure of the element feeder  26   a  will be described below. Regarding the other element feeders  26   b  to  26   d , the same parts and members as those of the element feeder  26   a  are denoted by the same reference signs in  FIG. 1 , and the description thereof will be omitted.  
      The element feeder  26   a  includes a take-out drum  28 . The take-out drum  28  is located directly under the hopper  16   a  to cover the exit of the hopper  16   a  with its outer circumferential surface from underneath. A large number of grooves (not shown) are formed in the outer circumferential surface of the take-out drum  28 , where the grooves are arranged at equal intervals in the circumferential direction of the drum  28 . Each groove of the take-out drum  28  receives a plain rod F A  from the hopper  16   a  while it is within the exit of the hopper  16   a , and the plain rod F A  received is held in the groove by suction. Thus, as the take-out drum  28  is rotated, the plain rods F A  are taken out of the hopper  16   a  one by one, each being held in a groove of the take-out drum  28 , and transported on the take-out drum  28 .  
      Further, a plurality of rotary knives  30  are provided onto the circumferential surface of the take-out drum  28 . During transportation, each plain rod F A  passes through the rotary knives  30  successively, where the rotary knives  30  cut the plain rod F A  successively, so that the plain rod F A  is divided into a plurality of filter elements f A , within the groove.  
      As shown in  FIG. 2 , directly under the take-out drum  28 , a guide path  32  in the form of a groove is provided. The guide path  32  extends towards the rear conveyor  18   r , and has a terminal end near the rear conveyor  18   r . Under the guide path  32 , an endless pusher chain  34  is disposed along the guide path  32 . The pusher chain  34  is arranged to pass around a drive sprocket  36  and around a driven sprocket  38 . The drive sprocket  36  is located near the beginning end of the guide path  32 , while the driven sprocket  38  is located in the downstream section of the guide path  32 . Thus, as clear from  FIG. 2 , the take-out drum  28  is arranged between the drive sprocket  36  and the driven sprocket  38 . Further, two pulleys are arranged under the guide path  32 . These pulleys guide the traveling of the pusher chain  34 , and one of these pulleys functions as a tension pulley to impart a specified tension to the pusher chain  34 . As the drive sprocket  36  is rotated, the pusher chain  34  travels along the guide path  32  in the upper portion of the chain  34 .  
      The pusher chain  34  has a plurality of pushers  40 . The pushers  40  have a claw-like shape and arranged on the pusher chain  34  at specified lengthwise intervals. While the pusher chain  34  is traveling, each pusher  40  periodically passes through the guide path  32 . For this, the guide path  32  has a slit (not shown) in the bottom thereof to allow the pushers  40  to pass.  
      The grooves of the take-out drum  28  successively arrive directly above the guide path  32 , where the pushers  40  of the pusher chain  33  each pass through the groove that has arrived directly above the guide path. Thus, as shown in  FIG. 3 , when plain rods F A  are received in the grooves of the take-out drum  28 , each pusher  40  pushes a plain rod F A  out of a groove of the take-out drum  28 , and the plain rod F A  pushed out is received on the guide path  32  and transported along the guide path  32  by being pushed by the pusher  40 .  
      Immediately before the pusher  40  pushes the plain rod F A  out of the take-out drum  28 , the suction for holding the plain rod F A  within the groove is removed, so that the plain rod F A  is smoothly pushed out of the take-out drum  28  by the pusher  40 .  
      As clear from  FIG. 2 , the guide path  32  includes an upslope ramp  32   a , and the upslope ramp  32   a  is located above the driven sprocket  38 . Thus, the plain rod FA transported along the guide path  32  gets on the upslope ramp  32   a  by being pushed by the pusher  40 , and then the pusher  40  goes below the upslope ramp  32   a , or in other words, the guide path  32 . Then, when the next pusher  40  pushes the succeeding plain rod F A  onto the upslope ramp  32   a , the succeeding plain rod FA butts against the preceding plain rod F A  already on the upslope ramp  32   a  and pushes the preceding plain rod F A  onward. Thus, the preceding plain rod F A  moves forward up the upslope ramp  32   a  by being pushed by the succeeding plain rod F A .  
      Meanwhile, above the guide path  32 , an endless acceleration belt  42  is provided. The acceleration belt  42  is arranged such that the plain rod F A  can be sandwiched between the acceleration belt  42  and the upslope ramp  32   a . The traveling speed of the acceleration belt  42  is higher than the traveling speed of the pusher chain  34 , and as mentioned above, the plain rod F A  pushed out of the take-out drum  28  is already divided into individual filter elements f A . Therefore, when the plain rod F A  moves forward up the upslope ramp  32  and the leading filter element f A  of the plain rod F A  becomes sandwiched between the acceleration belt  42  and the upslope ramp  32   a , the foremost filter element f A  is accelerated by the acceleration belt  42  and separated from the succeeding filter elements f A  as shown in  FIG. 4 . Thus, the filter elements f A  of the plain rod F A  which has passed through the acceleration belt  42  are separated individually with a specified interval between.  
      As clear from  FIG. 2 , the acceleration belt  42  is arranged to pass around the pulleys  42   a ,  42   b , and a toothed pulley  44  is mounted on the shaft of the pulley  42   a . Meanwhile, a toothed pulley  48  is mounted on the shaft of the driven sprocket  38 , where the toothed pulleys  44  and  48  are connected by a toothed belt  46 . Thus, when the pusher chain  34  is caused to travel, the acceleration belt  42  travels with the pusher chain  34 .  
      As shown in  FIG. 5 , the guide path  32  includes a curved path  32   b  in the downstream portion thereof, and the curved path  32   a  connects the upslope ramp  32   a  and the rear conveyor  18   r . Near the curved path  32   b , a feed wheel  50  is rotatably arranged. The circumferential surface of the feed wheel  50  extends corresponding to the curved path  32   b . The feed wheel  50  has a plurality of feed claws  52  on the circumferential surface thereof. The feed claws  52  project radially outward from the feed wheel  50  and arranged at equal intervals in the circumferential direction of the feed wheel  50 .  
      Further, a toothed pulley  54  is mounted on the shaft of the feed wheel  50 . Meanwhile, a toothed pulley  56  is arranged at a distance from the feed wheel  50 , where the toothed pulleys  54  and  56  are connected by an endless toothed belt  58 . Further, the toothed belt  58  passes around more than one guide pulley  60 , where the guide pulleys  60  impart a specified tension to the toothed belt  58 . When the toothed pulley  56  is rotated, the rotation of the toothed pulley  56  is transferred to the toothed pulley  54  and therefore to the feed wheel  50  by means of the toothed belt  58 , so that the feed wheel  50  rotates with the toothed pulley  56 .  
      During the rotation of the feed wheel  50 , each feed claw  52  of the feed wheel  50  periodically enters the curved path  32   b  and moves along the curved path  32   b . More specifically, as shown in  FIG. 4 , when a feed claw  52  enters the curved path  32   b , the feed claw  52  is located between a filter element f A  separated from a plain rod F A  by the acceleration belt  42  and the succeeding filter elements f A . Then, the feed claw  52  pushes out the separated filter element f A  to move along the curved path  32   b . Thus, the individual filter elements f A  are fed from the curved path  32   b  onto the rear conveyor  18   r , or in other words, onto the suction belt  22   r  at intervals, and sucked onto the suction belt  22   r . Then, the filter elements f A  are transported by the suction belt  22   r , being arranged in the direction of traveling of the suction belt  22   r  with a specified space between each other.  
      As clear from  FIG. 1 , in the same manner as the element feeder  26   a , the element feeder  26   b  takes charcoal rods F C  one by one out of the hopper  16   b  and feeds filter elements f C  produced by dividing the charcoal rods F C  onto the rear conveyer  18   r  at intervals. The feed position at which the filter element f C  is fed from the element feeder  26   b  onto the rear conveyor  18   r  is set upstream of the feed position at which the filter element f A  is fed from the element feeder  26   a  onto the rear conveyor  18   r , and the element feeder  26   a  feeds a filter element f A  onto the rear conveyor  18   r  so that the filter element f A  are distributed between filter elements f C . Thus, the filter elements f A  and f C  are transported, arranged in the direction of traveling of the rear conveyor  18   r  alternately and forming an element stream on the rear conveyor  18   r.    
      Meanwhile, the element feeders  26   c ,  26   d  feed filter elements f A , f C  onto the front conveyer  18   f , respectively, and the filter elements f A , f C  form, on the front conveyor  18   f , an element stream similar to the element stream on the rear conveyor  18   r.    
      The respective terminal ends of the front and rear conveyors  18   f ,  18   r  are connected to a downstream section  10   D  of the making machine.  
      The downstream section  10   D  includes front and rear forming paths  64   f ,  64   r  extending from the terminal ends of the front and rear conveyors  18   f ,  18   r , respectively. Each forming path  64  is aligned with the corresponding conveyor  18  and can receive the element stream from the corresponding conveyor  18 .  
      Near the beginning ends of the forming paths  64 , a wrapping apparatus  62  is provided. The wrapping apparatus  62  is schematically shown in  FIG. 6 . As the element streams are transported along the forming paths  64 , respectively, the wrapping apparatus  62  forms each element stream into a composite element rod.  
      In order to form the composite element rods, the wrapping apparatus  62  includes forming structures provided for the front and rear forming paths  64   f ,  64   r , respectively. Since both forming structures are similar, only one of them will be described below.  
      The forming structure includes a forming bed (not shown), and the forming bed extends along the forming path  64 . The forming bed has a forming groove (not shown) on the forming path  64 , and the forming groove guides the traveling of an endless garniture tape  66 . As clear from  FIG. 6 , the garniture tape  66  is arranged to pass around a drive drum  68 , and the drive drum  68  is shared by both forming paths  64   f ,  64   r.    
      As the drive drum  68  is rotated, the garniture tape  66  travels in the forming groove, where the direction of this traveling is the same as the direction of the traveling of the corresponding conveyor  18 . The traveling speed V G  of the garniture tape  66  is, however, lower than the traveling speed V S  of the conveyor  18 , or in other words, the suction belt  22 , and between the speeds V S , V G , there is, for example the relation 
 
 V   S =1.4× V   G . 
 
      A paper web W is fed onto the garniture tape  66 . The paper web W is unwound from a web roll (not shown). When the element stream is fed onto the forming path  64  from the corresponding conveyor  18 , the filter elements f A , f C  forming the element stream transfer onto the paper web W, and then, they are caused to travel with the paper web W by the garniture tape  66 .  
      More specifically, the forming structure includes a ranging path (not shown) which connects the forming groove in the forming bed and the conveyor  18 , and the element stream is fed from the conveyor  18  onto the paper web W via the ranging path.  
      Since the traveling speed V G  of the garniture tape  66 , or in other word, the paper web W is lower than the traveling speed V S  of the conveyor  18  and the ranging path extends between the forming bed and the conveyor  18 , the filter elements f A , f C  in the element stream chain-collide on the ranging path and form a composite element column C E  in which the filter elements f A , f C  are arranged alternately, in close contact with each other. Such composite element column C E  extends from the ranging path up to the terminal end of the conveyor  18 . Thus, the composite element column C E  is continuously fed onto the paper web W.  
      In the process of the paper web W being fed onto the garniture tape  66 , a glue is applied onto the paper web W by an applicator (not shown) to describe a rail-like pattern in the widthwise center of the paper web W. When the composite element column C E  is fed onto the paper web W, the rail-like glue on the paper web W sticks the composite element column C E  and the paper web W together, so that the composite element column C E  travels with the paper web W.  
      After this, the composite element column C E  is continuously wrapped in the paper web W and formed into a composite element rod ER, and the composite element rod ER is delivered from the wrapping apparatus  62 . It is to be noted that in  FIG. 6 , the composite element rod ER is shown with the paper web W removed, namely in the same manner as the composite element column C E .  
      In order to form the composite element rod ER, the forming structure includes, as shown in  FIG. 7 , a front tongue  70 , a rear tongue  72 , a short holder  74 , a long holder  76  and a water-cooling-type cooler  78 . These are arranged in this order from an upstream end of the forming path  64 . The forming structure further includes an air blow nozzles  80 ,  82 . The air blow nozzle  80  is located between the front tongue  70  and the rear tongue  72 , while the air blow nozzle  82  is located between the rear tongue  72  and the short holder  74 . The air blow nozzle  82  is not indispensable.  
      The front tongue  70  and the rear tongue  72  each cooperate with the forming groove in the forming bed to form a tunnel for the composite element column C E . While passing through the tongues  70 ,  72 , the paper web W is bent into a U-shaped cross section by the forming groove to cover the lower half of the composite element rod C E .  
      The air blow nozzle  80  jets out compressed air toward the downstream end of the front tongue  70 . The compressed air hits the part of the composite element column C E  that has come out of the front tongue  70  and exerts a specified braking force on the composite element column C E . More specifically, at this time, the rail-like glue has not completely stuck the composite element column C E  and the paper web W yet, so that the composite element column C E  is allowed to shift relative to the paper web W, in the direction of traveling of the paper web W.  
      Between the front tongue  70  and the rear tongue  72 , the braking force exerted on the composite element column C E  determines the positions of the filter elements f A , f C  relative to the paper web W, or in other words, the phase of the composite element rod C E , which will be described later.  
      After passing through the rear tongue  72 , the composite element rod C E  further receives a braking force exerted by compressed air from the air blow nozzle  82  as necessary, and then passes through the short holder  74  and the long holder  76  successively, with the paper web W.  
      The short holder  74  and the long holder  76  each include a heater (not shown) and function in the same way as the corresponding short and long holders of a cigarette making machine. Specifically, the short holder  74  and long holder  76  bend the opposite side parts of the paper web W around the upper half of the composite element column C E , successively, so that the opposite side edges of the paper web W overlap each other on the composite element column C E . The opposite side edges of the paper web W are stuck together with a lapping glue. At this time, the composite element column C E  is completely wrapped in the paper web W, thereby forming a composite element rod ER. The composite element rod ER formed is delivered from the long holder  76  along the forming path  64 .  
      To apply the lapping glue on the paper web W, an application nozzle (not shown) is disposed near the short holder  74 . While a side part of the paper web W is bent by the short holder  74 , the application nozzle continuously applies the lapping glue onto the other side edge of the paper web W.  
      The composite element rod ER delivered from the long holder  76  passes through the cooler  78 . The cooler  78  cools the composite element rod ER from above as well as from underneath, to promote the solidification of the lapping glue and rail-like glue.  
       FIG. 7  also shows a garniture tape  66  removal mechanism  84 .  
      The removal mechanism  84  includes a V-shaped link  86 . The link  86  is rotatably supported at the base thereof and comprises a pair of link arms. At the end of one of the link arms, a tension roller  88  is rotatably mounted. The tension roller  88  guides the traveling of the garniture tape  66  and also imparts a specified tension to the garniture tape  66 . The end of the other link arm is connected with the end of a piston rod of an air cylinder  90 . When the air cylinder  90  is contracted from the state shown, the V-shaped link  86  rotates clockwise in  FIG. 7 , thereby moving the tension roller  88  upward. Consequently, the tension is removed from the garniture tape  66 , so that the garniture tape  66  can be easily detached from the drive drum  68  and a large number of guide rollers.  
      After delivered from the wrapping apparatus  62 , the composite element rod ER passes through a cutting apparatus  92 . The cutting apparatus  92  cuts the composite element rod ER to a specified length, thereby forming individual filter rods FR.  
      More specifically, as shown in  FIG. 6 , the cutting apparatus  92  includes a cutting disk  94 . The cutting disk  94  is able to rotate in one direction and disposed under the composite element rod ER forming path  64 . The cutting disk  94  has a plurality of knives  96  on the circumferential surface thereof, where the knives  96  are arranged around the cutting disk  94  at equal intervals. As the composite element rod ER passes just above the cutting disk  94 , the knives  96  of the cutting disk  94  periodically cuts the composite element rod ER, thereby forming individual filter rods FR from the composite element rod ER. The filer rods FR formed has a fixed length.  
      It is to be noted that as clear from  FIG. 6 , the cutting disk  94  of the cutting apparatus  92  is shared by the front and rear forming paths  64   f ,  64   r  so that the knives  96  of the cutting disk  94  cut the composite element rods ER traveled along the forming paths  64   f ,  64   r  respectively.  
      Additionally, the cutting apparatus  92  includes a pair of split sleeves  98 . The split sleeves  98  are disposed on the front and rear forming paths  64   f ,  64   r , at locations just above the cutting disk  94 , respectively. The split sleeves  98  each guide the traveling of the corresponding composite element rod ER, and allow the knives  96  to pass across. Further, the front and rear forming paths  64   f ,  64   r  each include a transportation guide in the form of a groove (not shown). Each transportation guide extends from the cutting disk  94  to near the terminal end of the corresponding forming path. Each transportation guide guides the traveling of the filter rods FR delivered from the cutting apparatus  92 , where the filter rods are in close contact with each other.  
       FIG. 8  specifically shows filter rods FR obtained from the filter element rod ER. It is to be noted that also in  FIG. 8 , the filter element rod ER and filter rod FR are shown with the covering of the paper web W omitted.  
      In  FIG. 8 , the filter rod FR in (I) has a filter element f C  located in the center, filter elements f A  before and behind the filter element f C , and half-elements f CH  each adjacent to the end of a filter element f A , where the half-elements f C  are each formed by cutting a filter element f C  in two halves. That is, the filter rod FR like this is obtained by cutting the composite element rod ER at the center of every second filter element f C .  
      In order to obtain the filter rods FR like this, the circumferential speed of the cutting disk  94  of the cutting apparatus  92 , or in other words, the timing at which the knives  96  perform cutting is determined on the basis of the traveling speed of the garniture tape  66  (circumferential speed of the drive drum  68 ) or the traveling speed of the composite element rod ER. Meanwhile, the timing at which the individual filter elements f A , f C  are fed onto each conveyor  18  (circumferential speed of each feed wheel  50 ) is determined on the basis of the rotating speed of the cutting disk  94 .  
      More specifically, the drive drum  68  and the cutting disk  94  are connected by a power transmission path (not shown), while the toothed pulley  56  (see  FIG. 5 ) which determines the circumferential speed of the feed wheel  50  and the cutting disk  94  are connected by a power transmission path (not shown).  
      Each forming path  64  has a kicker roller  100  at the terminal end, where the kicker roller  100  is rotatably arranged just above the forming path  64 . When a leading filter rod FR on the forming path  64  reaches the kicker roller  100 , the kicker roller  100  accelerates and kicks out the leading filter rod FR, along the forming path  64 , forward. In this way, filter rods FR are delivered from the terminal end of the forming path  64 , at intervals.  
      Directly downstream of the front and rear forming paths  64   f ,  64   r , a drum train  102  is arranged. The drum train  102  extends from the terminal ends of the forming paths  64   f ,  64   r , horizontally and at right angles to the forming paths  64 . In this embodiment, the drum train  102  comprises a receiving drum  104  located at the beginning end thereof, and an inspection/removal drum  105  and an output drum  106  which range from the receiving drum  104  in this order. The drums  104 ,  105 ,  106  each have a plurality grooves (not shown) in the circumferential surface thereof, where the grooves are arranged around the drum at equal intervals.  
      As the receiving drum  104  is rotated, two circumferentially adjacent receiving grooves meet the terminal ends of the forming paths  64 , respectively, at the timing when the kicker rollers  100  kick out filter rods FR from the terminal ends of the front and rear forming paths  64   f ,  64   r , respectively, so that the two receiving grooves of the drum  104  can receive the filter rods FR kicked out from the forming paths  64 , respectively. In order to ensure that the receiving grooves receive the filter rods FR, the kicker rollers  100  kick out the filter rods FR in the direction deflected toward the direction of rotation of the receiving drum  104 .  
      After this, the filter rods FR in the receiving grooves are transported in the direction of circumference of the receiving drum  104 , then further transported by being received in receiving grooves in the inspection/removal drum  105  and in receiving grooves in the output drum  106 , successively, and then delivered from the output drum  106 . The filter rods FR delivered from the output drum  106  are received on a conveyor belt, and the conveyor belt transports the filter rods FR to a box packing machine.  
      As clear from the description above, the filter rods FR are transported in the manner that those kicked out from the front forming path  64   f  and those kicked out from the rear forming path  64   r  are arranged alternately on the drum train  102 . Thus, when another output drum is added to the drum train  102  to be adjacent to the output drum  106 , the filter rods FRf fed from the front forming path  64   f  and the filter rods FRr fed from the rear forming path  64   r  can be taken out separately by these output drums.  
      Above the inspection/removal drum  105 , an inspection camera  108  is arranged. The inspection camera  108  images the filter rods FRf, FRr transported on the inspection/removal drum  105 , and transmits the images of the filter rods FR to an inspection circuit  110  as image data Df, Dr.  
      The inspection circuit  110  determines whether or not the filter rods FRf, FRr are non-defective, on the basis of the image data Df, Dr, and sends control signals Sf, Sr to a phase change apparatus  112  on the basis of the inspection result. On the basis of the control signals Sf, Sr, the phase change apparatus  112  can change the feed phases of the composite element columns C Ef , C Er  fed to the front and rear forming paths  64   f ,  64   r , or in other words, the transportation phases of the filter elements f A , f C  on the front and rear conveyors  18   f ,  18   r . The details of the phase change apparatus  112  will be described later.  
      Next, the function of the inspection circuit  110  will be described specifically.  
      When the image data D transmitted from the inspection camera  108  to the inspection circuit  110  is obtained from a normal filter rod FR shown in (I) of  FIG. 8 , the half-elements f CH  at the opposite ends of the filter rod FR are each equal to half of the filter element f C . In this case, the inspection circuit  110  determines that the filter rod FR in (I) of  FIG. 8  is non-defective, and does not send out a control signal S.  
      The filter element f C  contains activated charcoal particle. Therefore, even though the filter rod FR is covered with the paper web W, the image of the filter rod FR shows different densities. Specifically, the part of the image indicating the filter element f C  is higher in density than the part of the image indicating the filter element f A , so that in the image, a clear boundary is produced between the half-element f CH  and the filter element f A  due to the difference in density. Thus, the inspection circuit  110  can detect the length L of the half-element f CH  by measuring the distance from an end of the filter rod FR to such boundary.  
      Preferably, the above-mentioned end of the filter rod FR is the leading end of the filter rod FR transported along the formation path  64 .  
      Since the timing at which the cutting apparatus  92  performs cutting is definitely determined on the basis of the traveling speed of the garniture tape  64  as already mentioned, when the length L of the half-element f CH  at the leading end of the filter rod FR is equal to half L O  of the length of the filter element f C , also the length L of the half-element f CH  at the tail end of the filter rod FR is equal to the length L O .  
      There are, however, cases in which the formation of the composite element rod ER by the wrapping apparatus  62  undergoes negative influence due to some reason, so that filter rods FR like those shown in (II) and (III) of  FIG. 8  are formed. In the case (II), the length L of the half-element f CH  at the leading end of the filter rod FR is smaller than the length L O , while the length L of the half-element f CH  at the tail end is greater than the length L O . This means that a phase advance a is produced in the transportation of the composite element column E C . In this case, the inspection circuit  110  determines that the filter rod FR is defective, and on the basis of the difference ΔL (=L O −L) between the length L O  and the length L of the half-element f CH , feeds a control signal S for advancing the transportation phase of the composite element column C E , to the phase change apparatus  112 . Meanwhile, in the case (III), the length L of the half-element f CH  at the leading end of the filter rod FR is greater than the length L O , while the length L of the half-element f CH  at the tail end is smaller than the length L O . This means that a phase delay d is produced in the transportation of the composite element column E C . In this case, on the basis of the difference ΔL, the inspection circuit  110  feeds a control signal S for delaying the transportation phase of the composite element column C E , to the phase change apparatus  112 .  
      An example of the phase change apparatus  112  is shown in  FIG. 9 .  
      The phase change apparatus  112  is interposed in each power transmission path which connects the toothed pulley  56  of each element feeder  26   a  to  26   d  and the cutting disk  94  of the cutting apparatus  92 . More specifically, the phase change apparatus  112  includes a triaxial differential gear mechanism  116 . The differential gear mechanism  116  connects the toothed pulley  56  and an output gear  114  located at the terminal end of the power transmission path.  
      The differential gear mechanism  116  includes a gear casing  118 , and the gear casing  118  has an input shaft  120  and an output shaft  122 . The input shaft  120  and the output shaft  122  are aligned with each other, and each rotatably fitted to the gear casing  118  by means of a bearing  124 . The output gear  114  is mounted on the input shaft  120 , while the toothed pulley  56  is mounted on the output shaft  122 .  
      The input shaft  120  and the output shaft  122  are connected by means of a Harmonic Drive (registered trademark)  126 . The Harmonic Drive  126  comprises a wave generator  128 , a flex spline  130  and a circular spline  131  arranged in this order from the center. The wave generator  128  is mounted on a correction shaft  132 , and the correction shaft  132  is coaxially arranged within the input shaft  120 , and has an end projecting beyond the input shaft  120 .  
      An output shaft  136  of a step motor  134  is connected with this end of the correction shaft  132 , where the step motor  134  is operated on the basis of the control signal S from the inspection circuit  110 .  
      When the step motor  134  is stopped, the rotation of the input shaft  120  is transferred to the output shaft  122  via the Harmonic Drive  126 , so that the output shaft  122  rotates in phase with the input shaft  120 . Consequently, the feed wheel  50  rotated by the toothed pulley  56  on the output shaft  122  is rotated with the phase corresponding to the rotation phase of the input shaft  120  and feeds filter elements f onto the conveyor  18 . In other words, the feed phase of the filter element f fed onto the conveyor has a fixed relationship with the timing of cutting the composite element rod ER, which is determined by the rotation phase of the input shaft  120 .  
      When, however, a control signal S is fed from the inspection circuit  110  to the step motor  134 , the step motor  134  rotates the correction shaft  132  in one direction according to the control signal S. This rotation of the correction shaft  132  operates the Harmonic Drive  126  to advance or delay the rotation phase of the feed wheel  50  (output shaft  122 ) relative to the timing of cutting the composite element rod ER (rotation phase of the input shaft  120 ). Therefore, the timing of feeding the filter element f A , f C  from the feed wheel  50  onto the conveyor  18 , or in other words, the transportation phase of the filter element f A , f C  on the conveyor  18  changes.  
      Consequently, the feed phase of the composite element column C E  fed from the conveyor  18  onto the forming path  64 , or in other words, the transportation phase of the composite element column C E  on the conveyor  18  is advanced or delayed, so that filter rods FR formed after this become non-defective ones as shown in (I) of  FIG. 8 .  
      It is to be noted that the above-described correction control on the transportation phase is carried out for each of the front and rear conveyors  18   f ,  18   r , independently, where the rotation phases of the two feed wheels  50  associated with the same conveyor  18  are advanced or delayed together, on the basis of the same control signal S. It is also to be noted that defective filter rods FR as shown in (II) and (III) of  FIG. 8  are removed from the inspection/removal drum  105 .  
      Next, referring to  FIG. 10 , how the transportation phase of the composite element column C E  changes will be described.  
      Since the filter element f (f A , f C ) fed onto the conveyor  18  by the feed claw  52  is sucked onto the suction belt  22 , the initial speed V f1  of the filter element f agrees with the traveling speed V S  of the suction belt  22 .  
      Since the traveling speed V G  of the garniture tape  66  is lower than the traveling speed V S  as mentioned above and the composite element column C E  extending from the front tongue  70  on the forming path  64  reaches the terminal end of the conveyor  18 , the conveyor  18  travels in sliding contact with the composite element column C E . Thus, when a filter element f newly fed onto the conveyor  18  butts against the tail end of the composite element column C E , the traveling speed V f2  of the filter element f is reduced from the initial speed V f1  to the traveling speed of the composite element column C E , i.e., the traveling speed V G  of the garniture tape  66 .  
      Meanwhile, a pushing-out force F S  is exerted on the composite element column C E  on the conveyor  18  and a slight dragging force F G  is exerted on the composite element column C E  on the garniture tape  66  in the direction of traveling of the composite element column C E , where the resultant force F F  on the composite element column C E  which pushes the composite element column C E  forward is represented by the expression 
 
 F   F   =F   S   +F   G . 
 
      The pushing-out force F S  is determined on the basis of a frictional force between the composite element column C E  and the suction belt  22  and a resistance which the ranging path exerts on the traveling composite element column C E , while the dragging force F G  is determined on the basis of a friction between the composite element column C E  and the garniture tape  66 .  
      In addition to the above-mentioned pushing-forward force F F , a braking force F B  is also exerted on the composite element column C E . The braking force F B  is determined on the basis of a resistance which the compressed air jetted from the air nozzle  80  exerts on the traveling composite element column C E  and a resistance which the front tongue  70  exerts on the traveling composite element column C E .  
      When a filter element f of the composite element column C E  comes out of the front tongue  70  and reaches a position where the compressed air from the air blow nozzle  80  does not hit it, the filter element f no longer receives the braking force F B  and only receives the pushing-forward force F F .  
      Thus, as shown in  FIG. 10 , just downstream of the front tongue  70 , a slight space X is produced between the filter element f and the succeeding filter element f of the composite element column C E . This space X is, however, removed when the composite element column C E  passes through the rear tongue  72 , due to a resistance which the rear tongue  72  exerts on the traveling filter element f and a braking force which compressed air jetted from the air blow unit  82  exerts on the filter element f. Consequently, after passing through the rear tongue  72 , the filter elements f of the composite element column C E  can be in close contact with each other.  
      When the pushing-forward force F F  is constant, the space X is kept constant. When, however, the pushing-forward force F F  is increased, the space X becomes greater, and when the pushing-forward force F F  is decreased, the space X becomes smaller.  
      Meanwhile, when the rotation phase of the feed wheel  50  is advanced, the pushing-forward force F F  tends to be increased, and when the rotation phase of the feed wheel  50  is delayed, the pushing-forward force F F  tends to be decreased. Such increase or decrease in the pushing-forward force F F  is thought to be caused by increase or decrease in the length of the composite element column C E  formed on the path between the feed wheel  50  and the front tongue  70 , or in other words, increase or decrease in the frictional force between the composite element column C E  and the suction belt  22  when the rotation phase of the feed wheel  50  is changed.  
      Thus, by controlling the rotation phase of the feed wheel  50  on the basis of the control signal S as mentioned above, the space X can be varied. The variation in the space X advances or delays the transportation phase of the composite element column C E  between the rear tongue  72  and the short holder  74 . Consequently, the cutting position on the composite element rod ER can be changed without changing the timing at which the cutting apparatus  92  performs cutting.  
      The present invention is not restricted to the above-described embodiment. Various modifications can be made to it.  
      For example, the phase change apparatus  112  can use various types of differential gear mechanisms and servo mechanisms in place of the Harmonic Drive  126 .  
      The front and rear conveyor tracks  18   f ,  18   r  can each include a rotatable alignment drum at the terminal end, where the alignment drum has a plurality of spiral grooves in the circumferential surface thereof. The alignment drum receives a specified number of filter elements f in the spiral grooves from the corresponding conveyor  18 , and the spiral grooves feed the filter elements f to the forming path  64 , in close contact with each other, at intervals. In this case, the phase change apparatus  112  can change the transportation phase of the composite element column C E  on the forming path  64 , by advancing or delaying the rotation phase of the alignment drum on the basis of a control signal S.  
      Further, the combination and the number of filter elements f constituting a filter rod FR are not restricted to those in the described embodiment but can be changed in various ways.