Low ignition propensity (lip) paper smoking articles

Abstract

Apparatus for producing low ignition propensity (“LIP”) smoking articles provides independent control of the belt drive transport speed and the cutting head rotational speed in dependence on the relative position of the cutting head blades to the position of the continuous tobacco column on the tape drive, by detecting the presence of synchronizing marks disposed on the outer surface of the tobacco column LIP paper wrapper, thereby controlling cutting of the continuous column to provide registration of the LIP paper's LP bands to their designated location within the finished article's tobacco column.

1 . A method of manufacturing low ignition propensity (LIP) smoking articles having a tobacco column of desired length with a low porosity (LP) band pattern disposed thereon, comprising: 
 providing a continuous strip of LIP material wrapper having LP bands disposed on a major surface thereof, in interleaved fashion with untreated material areas, to provide a longitudinally extending array of LP band pattern panels, each said LP band pattern panel having one or more LP bands disposed along its panel length, said panel length extending longitudinally, between panel boundaries, at a distance substantially equal to the desired length of the LIP smoking article tobacco column, the LIP material wrapper further having synchronizing marks disposed longitudinally there along, in known axial relation to said panel boundaries and at substantially equal pitch intervals, said synchronizing marks being physically detectable from the LIP material wrapper surface;    wrapping tobacco filler within the LIP material wrapper along a top stretch of a moving conveyor belt to form a continuous LIP material wrapped tobacco column having synchronizing marks appearing there along, and transporting said continuous LIP material wrapped tobacco column, at a tobacco column transport speed proportional to the conveyor belt speed, to a cutting location;    cutting the continuous LIP material wrapped tobacco column at the cutting location, at a selected cutting speed, into the desired cut length tobacco columns;    as characterized by:    monitoring the values of said cutting speed and said conveyor belt speed;    detecting passage of succeeding ones of said synchronization marks on said LIP wrapped tobacco column past a reference point located along the tobacco column travel path, at a reference distance upstream from the cutting location, and providing a synchronizing mark signal pulse in response to each such detection, said synchronizing mark signal pulses individually providing a sensed representation of the position of the LP band panels with respect to the cutting location and collectively providing a sensed synchronization mark signal having a pulse repetition frequency proportional to the instant tobacco column transport speed past the reference location; and    adjusting the conveyor belt speed as necessary to synchronize the sensed location of the LP band panel, as represented by said synchronizing mark signal pulse, and the tobacco column transport speed, as represented by said synchronizing signal pulse repetition frequency, to the monitored cutting speed to provide cutting of the continuous tobacco column at axial cutting positions outside of said LP band pattern panel boundaries, thereby providing LIP smoking articles having a tobacco column with a registered LP band pattern.    
   
   
       2 . The method of  claim 1 , where one or more of said LP bands are located in a defined arrangement within each said LP band pattern panel.  
   
   
       3 . The method of  claim 1 , where said pitch interval spacing of said synchronizing marks is proportional to the desired length of the smoking article tobacco column.  
   
   
       4 . The method of  claim 3 , where said pitch interval value is a whole number multiple of the desired length of the smoking article tobacco column.  
   
   
       5 . The method of  claim 4 , where said pitch interval is twice the desired length of the smoking article.  
   
   
       6 . The method of  claim 3 , where said synchronizing marks are in the form of stripes which extend a proportionate part of the width of said continuous strip of LIP material wrapper.  
   
   
       7 . The method of  claim 6 , where said synchronizing marks extend a proportionate part of the width of said continuous strip of LIP material wrapper, sufficient to permit physical detection of said synchronizing marks from the LIP material wrapper surface along an appreciable length arc of said LIP material wrapped tobacco column circumference.  
   
   
       8 . The method of  claim 6 , where said synchronizing marks extend the width of continuous strip of LIP material wrapper.  
   
   
       9 . The method of  claim 7 , where said synchronizing marks extend from an edge of said continuous strip of LIP material wrapper at a length no less than one fifth the width of said strip.  
   
   
       10 . The method of  claim 5 , where said synchronizing marks are disposed at alternating ones of said axial cutting positions, each such alternating axial cutting position occurring at the end of cut length tobacco columns at which the a smoking article filter is to be attached with tipping paper to provide a filtered LIP smoking article, whereby any post cutting residue of the synchronizing mark is covered by the tipping paper.  
   
   
       11 . The method of  claim 1 , where said synchronizing marks are disposed at said LP band pattern panel boundaries.  
   
   
       12 . The method of  claim 10 , where said LP band pattern panels and said synchronizing marks are disposed on a common major surface of said continuous strip of LIP material wrapper.  
   
   
       13 . The method of  claim 10 , where said LP band pattern panels and said synchronizing marks are disposed on opposite major surfaces of the LIP material strip.  
   
   
       14 . The method of  claim 1 , wherein the synchronizing marks have sufficient contrast to the LIP material wrapped tobacco column surface to be detected by physical means.  
   
   
       15 . The method of  claim 14 , where the synchronizing marks may be detected at a resolution accuracy no greater than plus or minus 0.2 millimeters of their actual position on the continuous LIP material tobacco column, at a mark signal frequency of substantially 100 pulses per second.  
   
   
       16 . The method of  claim 14 , where said synchronizing marks have at least thirty percent higher light reflectivity than the LIP material surface.  
   
   
       17 . The method of  claim 16 , where said synchronizing marks are optically detected.  
   
   
       18 . The method of  claim 17 , where the synchronizing marks are detected using red wavelength laser light.  
   
   
       19 . The method of  claim 1 , where the synchronizing marks are in the form of stripes disposed transverse to the length of the strip, and having a stripe length which extends a proportionate part of the width of the strip.  
   
   
       20 . The method of  claim 19 , where said synchronizing mark stripes extend a proportionate part of the width of the strip sufficient to permit their physical detection along an arc which is no less than one fifth the circumference of said continuous LIP wrapped tobacco column.  
   
   
       21 . The method of  claim 19 , where said synchronizing mark stripes have a width no greater than two millimeters.  
   
   
       22 . The method of  claim 1 , further comprising: 
 inserting a double length filter section between succeeding smoking article cut length tobacco columns and attaching the distal ends of said filter section with tipping paper to the cut end of the smoking article cut length tobacco column immediately adjacent thereto, said tipping paper overlapping an end surface portion of each such joined tobacco column; and    cutting the joined tobacco columns substantially at the center of the filter section to produce a finished product LIP smoking article.    
   
   
       23 . The method of  claim 22 , where said synchronizing mark stripes are located at the end of the cut length tobacco column which receives said filter section, whereby said synchronizing marks are covered by said tipping paper in the finished product LIP smoking article.  
   
   
       24 . The method of  claim 1 , where said reference distance is no greater than twice said mark interval spacing.  
   
   
       25 . The method of  claim 24 , where said reference distance is substantially equal to said mark interval spacing.  
   
   
       26 . The method of  claim 1 , further comprising: 
 specifying the length tolerance limits for an acceptable LIP smoking article tobacco column length, and quantifying the specified length tolerance in terms of a synchronization tolerance indicative of the acceptable degree of non-synchronization between the sensed synchronization signal and the monitored cutting speed;    determining the maximum synchronization correction that a change in belt speed can provide within the cutting time interval between successive cut length tobacco columns;    monitoring the value of synchronization correction provided within the cutting time interval for each cut length of tobacco column, and identifying as defective product, those cut length tobacco columns provided in a cutting time interval in which the non-synchronization magnitude exceeded the maximum synchronization correction value; and    discarding the defective product prior to the step of inserting the double length filter section.    
   
   
       27 . Apparatus for manufacturing LIP smoking articles having a desired length tobacco column with a registered LP band pattern, comprising: 
 bobbin means, for providing a continuous strip of LIP material wrapper of the type having LP bands disposed on a major surface thereof, in interleaved fashion with untreated material areas, to provide a longitudinally extending array of LP band pattern panels, each said LP band pattern panel having one or more LP bands arranged in said interleaved fashion along its panel length, said panel length extending longitudinally, between panel boundaries, at a distance substantially equal to the desired length of the LIP smoking article tobacco column, the LIP material wrapper further having synchronizing marks disposed longitudinally there along, in known axial relation to said panel boundaries and at substantially equal pitch intervals, said synchronizing marks being physically detectable from the LIP material surface;    conveyor means, having a conveyor belt moving at belt speed for receiving the continuous strip LIP material at a top stretch area thereof where tobacco filler is rolled in the continuous strip LIP material wrapper to form a continuous LIP material wrapped tobacco column having synchronizing marks appearing therealong, the conveyor belt transporting the continuous LIP material wrapped tobacco column to a cutting location at a column transport speed proportional to said belt speed; and    cutting head means, having one or more cutting blades which cycle at a cutting head speed through the cutting location to cut the continuous LIP material wrapped tobacco column into the desired length tobacco columns;    as characterized by:    conveyor belt motive means, including a belt motor with rotating shaft for moving the conveyor belt at said belt speed, a belt motor shaft sensor for providing a sensed belt feedback signal representative of the instant rotational speed of said belt motor shaft, and belt motor control means for controlling the conveyor belt speed in response to said sensed belt feedback signal and to belt motor command signals presented thereto;    cutting head motive means, having a cutting head motor with rotating shaft for cycling said cutting head blades at said cutting head speed through said cutting location, a cutting head motor shaft sensor for providing a sensed cutting head feedback signal representative of the instant rotational speed of said cutting motor rotating shaft, and cutting head motor control means for controlling the cutting head speed in response to said sensed cutting head feedback signal and to said cutting head motor command signals presented thereto;    tobacco column sensor means, for detecting the passage of succeeding ones of said synchronization marks on said LIP wrapped tobacco column past a reference point located along the tobacco column travel path, at a reference distance upstream from the cutting location, and providing a synchronizing mark signal pulse in response to each such detection, said synchronizing mark signal pulses individually providing a sensed representation of the position of the LP band panels with respect to said cutting location and collectively providing a sensed synchronization mark signal having a pulse repetition frequency proportional to the instant tobacco column transport speed past said reference location; and    supervisory control means, having memory means for storing signal information, including the occurrence of said sensed synchronizing mark signal pulse representation of the position of the LP band panels with respect to said cutting location and said sensed synchronization mark signal pulse repetition frequency, said supervisory control means being responsive to said sensed synchronizing mark signal pulses, said sensed synchronization mark signal pulse repetition frequency, said sensed belt feedback signal, and said sensed cutting head feedback signal, to provide, in response thereto, belt motor command signals to the conveyor belt motor means to adjust said conveyor belt speed as necessary to synchronize the sensed location of the LP band panel, as represented by said synchronizing mark signal pulse, and the tobacco column transport speed, as represented by said synchronizing signal pulse repetition frequency, to the monitored cutting speed to provide cutting of the continuous tobacco column at axial cutting positions outside of said LP band pattern panel boundaries, thereby providing LIP smoking articles having a tobacco column with a registered LP band pattern.    
   
   
       28 . The apparatus of  claim 27 , where the synchronizing marks are disposed at the LIP material panel boundaries.  
   
   
       29 . The apparatus of  claim 28 , further comprising: 
 filter assembly means, for receiving the cut length tobacco columns and inserting, between each succeeding two cut length tobacco columns, a double length filter section, the filter assembly means attaching the distal ends of the filter section with tipping paper to the ends of the cut length tobacco columns immediately adjacent thereto, the tipping paper overlapping an end surface portion of each such joined tobacco column; and    filter cutting means, for cutting the joined columns at substantially the center of the filter section to produce a finished product LIP smoking article.    
   
   
       30 . The apparatus of  claim 29 , where the mark interval spacing is substantially equal to two panel lengths.  
   
   
       31 . The apparatus of  claim 27 , where the synchronizing marks have sufficient contrast to the LIP material wrapped tobacco column surface to be detected by physical means.  
   
   
       32 . The apparatus of  claim 31 , where the synchronizing marks may be detected at a resolution accuracy no greater than plus or minus 0.2 millimeters of their actual position on the continuous LIP material tobacco column, at a mark signal frequency of substantially 100 pulses per second.  
   
   
       33 . The apparatus of  claim 31 , where the synchronizing marks have at least thirty percent higher light reflectivity than the LIP material surface.  
   
   
       34 . The apparatus of  claim 33 , where the synchronizing marks are optically detected.  
   
   
       35 . The apparatus of  claim 34 , where the synchronizing marks are detected using red wavelength laser light.  
   
   
       36 . The apparatus of  claim 33 , where the synchronizing marks are in the form of stripes disposed transverse to the length of the strip, and having a stripe length which extends a proportionate part of the width of the strip.  
   
   
       37 . The apparatus of  claim 27 , where the synchronizing mark stripes extend a proportionate part of the width of the strip sufficient to permit their physical detection along an arc which is no less than one fifth the circumference of the continuous LIP wrapped tobacco column.  
   
   
       38 . The apparatus of  claim 37 , where the synchronizing mark stripes have a width no greater than two millimeters.  
   
   
       39 . The apparatus of  claim 29 , where the synchronizing mark stripes are located at the end of the cut length tobacco column which receives the filter section, whereby the synchronizing marks are covered by the tipping paper in the finished product LIP smoking article.  
   
   
       40 . The apparatus of  claim 27 , where said reference distance is no greater than twice the mark interval spacing.  
   
   
       41 . The apparatus of  claim 27 , where said reference distance is substantially equal to the mark interval spacing.  
   
   
       42 . The apparatus of  claim 27 , further comprising: 
 user interface means, responsive to operator control, for receiving operator entered specification signals which defines the maximum synchronization correction that a change in belt speed may provide within a cutting time interval, and a maximum non-synchronization error magnitude, beyond which the apparatus produces unacceptable cut length tobacco columns, the supervisory control means monitoring the non-synchronizing error magnitude in each cutting time interval and identifying, as defective products to be ejected by the apparatus prior to the filter assembly means, those cut length tobacco columns produced in cutting time intervals in which the non-synchronization magnitude exceeds the maximum non-synchronization error magnitude.    
   
   
       43 . The apparatus of  claim 27 , where said LP band pattern panels and said synchronizing marks are disposed on a common major surface of said continuous strip of LIP material wrapper.  
   
   
       44 . The apparatus of  claim 27 , where said LP band pattern panels and said synchronizing marks are disposed on opposite major surfaces of the LIP material strip.  
   
   
       45 . LIP strip material tobacco wrapper for use in apparatus for manufacturing LIP smoking articles having a desired length tobacco column, comprising: 
 strip material, having opposing major surfaces and a material porosity there between suitable for use as conventional smoking article tobacco wrapper;    LP bands disposed on one of the strip material major surfaces in interleaved fashion with untreated material areas, to provide a longitudinally extending array of LP band pattern panels, the LP bands extending substantially the width of the strip material, transverse to its length, and interleaved along the length of the strip with untreated material areas, in a repeating, longitudinally extended array of LP band pattern panels, each pattern panel having one or more LP bands interleaved with untreated sheet material areas within a panel length thereof, the panel length extending longitudinally between panel boundaries at a distance substantially equal to the desired length of the LIP smoking article tobacco column; and    synchronizing marks disposed on one of the strip material major surfaces, the synchronizing marks being disposed in spaced apart fashion along the length of strip, at mark interval spacing proportional to panel length to locate the synchronizing marks along the strip length in known axial relationship to the pattern panels, the synchronizing marks having sufficient contrast to the sheet material surface on which they are disposed to be physically detected by physical means.    
   
   
       46 . The LIP strip material tobacco wrapper of  claim 45 , where the synchronizing marks are disposed at the LIP material panel boundaries.  
   
   
       47 . The LIP strip material tobacco wrapper of  claim 45 , where the mark interval spacing is substantially equal to two panel lengths.  
   
   
       48 . The LIP strip material tobacco wrapper of  claim 45 , where the synchronizing marks have sufficient contrast to the LIP material wrapped tobacco column surface to be detected by physical means.  
   
   
       49 . The LIP strip material tobacco wrapper of  claim 48 , where the synchronizing marks may be detected within a sensed resolution of plus or minus 0.2 millimeters when the LIP strip material synchronizing mark array is scanned by physical means at a relative scanning rate of 100 synchronizing marks per second.  
   
   
       50 . The LIP strip material tobacco wrapper of  claim 48 , where the synchronizing marks have at least thirty percent higher light reflectivity than the LIP material surface.  
   
   
       51 . The LIP strip material tobacco wrapper of  claim 48 , where the synchronizing marks are optically detected.  
   
   
       52 . The LIP strip material tobacco wrapper of  claim 51  where the synchronizing marks are detectable with a red wavelength laser light.  
   
   
       53 . The LIP strip material tobacco wrapper of  claim 45 , where the synchronizing marks are in the form of stripes disposed transverse to the length of the strip, and having a stripe length which extends a proportionate part of the width of the strip.  
   
   
       54 . The LIP strip material tobacco wrapper of  claim 53 , where the synchronizing mark stripe length extends at least one fifth the width of the LIP strip material.  
   
   
       55 . The LIP strip material tobacco wrapper of  claim 54 , where the synchronizing mark stripes have a width no greater than two millimeters.  
   
   
       56 . The LIP strip material tobacco wrapper of  claim 45 , where the LIP strip material comprises paper tobacco wrapper.  
   
   
       57 . The LIP strip material tobacco wrapper of  claim 45 , where the LP bands and the synchronizing marks are disposed on the opposite side major surfaces of the LIP strip material.  
   
   
       58 . A low ignition propensity (LIP) smoking article, comprising: 
 a tobacco column,    one or more low porosity (LIP) bands disposed on said tobacco column at a location thereon which is dependent on its relative position there along to one or more synchronizing marks similarly disposed on said tobacco column in known axial relation to said LP bands.