U.S. patent application number 10/861474 was filed with the patent office on 2004-11-04 for method of and apparatus for ascertaining parameters of cigarette paper and the like.
This patent application is currently assigned to Hauni Maschinenbau AG. Invention is credited to Schroder, Dierk.
Application Number | 20040216755 10/861474 |
Document ID | / |
Family ID | 7708431 |
Filed Date | 2004-11-04 |
United States Patent
Application |
20040216755 |
Kind Code |
A1 |
Schroder, Dierk |
November 4, 2004 |
Method of and apparatus for ascertaining parameters of cigarette
paper and the like
Abstract
The invention relates to a method of and to an apparatus for
ascertaining at least one parameter of cigarette paper or the like,
such as a running web of cigarette paper at least one side of which
carries or should carry longitudinally spaced-apart coatings, e.g.,
consisting of silicate or cellulose and suitable to serve as
so-called burning or combustion stops. A source of electromagnetic
radiation cooperates with a polarizer to direct radiation against
one side of the running web at an angle of between about 0.degree.
and 75.degree. to the plane of the web at the locus of impingement
of radiation. The radiation which has penetrated through the web is
measured by a photosensitive detector which transmits corresponding
signals to an evaluating arrangement serving to ascertain one or
more characteristics of the coatings.
Inventors: |
Schroder, Dierk; (Hamburg,
DE) |
Correspondence
Address: |
VENABLE, BAETJER, HOWARD AND CIVILETTI, LLP
P.O. BOX 34385
WASHINGTON
DC
20043-9998
US
|
Assignee: |
Hauni Maschinenbau AG
Hamburg
DE
|
Family ID: |
7708431 |
Appl. No.: |
10/861474 |
Filed: |
June 7, 2004 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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10861474 |
Jun 7, 2004 |
|
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PCT/EP02/13339 |
Nov 27, 2002 |
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Current U.S.
Class: |
131/280 ;
131/365; 162/139 |
Current CPC
Class: |
G01N 21/59 20130101;
A24C 5/005 20130101 |
Class at
Publication: |
131/280 ;
131/365; 162/139 |
International
Class: |
D21F 011/00; D21H
011/00 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 7, 2001 |
DE |
101 60 235.9 |
Claims
What is claimed is:
1. A method of ascertaining at least one parameter of cigarette
paper, comprising the steps of: directing against one side of the
cigarette paper at least one beam of electromagnetic radiation at
an incidence angle .alpha. of between 0.degree. and 75.degree.
whereby a portion of said radiation issues from and at the other
side of the cigarette paper; measuring the issuing radiation; and
ascertaining said at least one parameter as a function of said
issuing radiation.
2. The method of claim 1, wherein said angle .alpha. is between
about 5.degree. and 45.degree..
3. The method of claim 1, wherein said angle .alpha. is between
about 10.degree. and 20.degree..
4. The method of claim 3, wherein said angle .alpha. is about
15.degree..
5. The method of claim 1, further comprising the step of detecting
said radiation issuing from and at the other side of the cigarette
paper at a predetermined angle .beta. with respect to the other
side of the cigarette paper.
6. The method of claim 5 wherein said angle .beta. is between about
45.degree. and 90.degree..
7. The method of claim 6, wherein said angle .beta. is between
about 70.degree. and 90.degree..
8. The method of claim 1, wherein said electromagnetic radiation
has a predetermined polarized condition.
9. The method of claim 8, wherein said electromagnetic radiation is
linearly polarized parallel to the one side of the cigarette
paper.
10. The method of claim 1, further comprising the step of advancing
the cigarette paper in a predetermined direction, said at least one
parameter involving the presence of essentially periodical coatings
provided at least at one of said sides of the cigarette paper and
entailing essentially periodical changes of intensity of radiation
issuing from the cigarette paper at a locus of impingement of
electromagnetic radiation against said one side of the advancing
cigarette paper.
11. The method of claim 10, wherein said determining step includes
determining the periods of said changes of radiation and said
ascertaining step includes comparing the determined periods of said
changes of radiation with a predetermined period.
12. The method of claim 11, further comprising the step of
ascertaining the extent of said changes of radiation and said
predetermined period includes an interval of average value of
intensity of radiation which is characteristic of at least one
constituent of the material of said coating.
13. Apparatus for ascertaining at least one parameter of cigarette
paper, comprising; a source of electromagnetic radiation; means for
directing a beam of radiation from said source against one side of
the cigarette paper at an angle .alpha. of between about 0.degree.
and 75.degree. whereby a portion of such radiation issues from and
at the other side of the cigarette paper; detector means arranged
to measure the issuing radiation; and means for ascertaining the at
least one parameter of cigarette paper as a function of said
issuing radiation.
14. The apparatus of claim 13, wherein said angle .alpha. is
between about 5.degree. and 45.degree..
15. The apparatus of claim 13, wherein said angle .alpha. is
between about 10.degree. and 20.degree..
16. The apparatus of claim 15, wherein said angle .alpha. is about
15.degree..
17. The apparatus of claim 13, wherein said detector means is
positioned to intercept radiation issuing from and at the other
side of the cigarette paper at a predetermined angle g with respect
to the cigarette paper.
18. The apparatus of claim 17, wherein said angle .beta. is between
about 45.degree. and 90.degree..
19. The apparatus of claim 17, wherein said angle .beta. is between
about 70.degree. and 90.degree..
20. The apparatus of claim 13, further comprising means for
polarizing the radiation issuing from said source before the
radiation reaches the cigarette paper.
21. The apparatus of claim 20, wherein said polarizing means is
arranged to polarize the radiation issuing from said source in
parallel to said one side of the cigarette paper.
22. The apparatus of claim 13, further comprising means for
advancing the cigarette paper along a predetermined path, said
detector means being arranged to monitor the intensity of radiation
issuing from the cigarette paper and said at least one parameter
including the presence of essentially periodical coatings provided
at least at one of said sides of the cigarette paper in said path
and entailing essentially periodical changes of intensity of
radiation reaching said detector means subsequent to penetration
through the web in a predetermined portion of said path.
23. The apparatus of claim 22, wherein said ascertaining means
comprises a memory operatively associated with said detector means
and arranged to store a predetermined period of changes for
comparison with changes represented by the radiation determined by
said detector means.
24. The apparatus of claim 23, wherein said memory includes a table
denoting the extent of said changes of radiation and said
predetermined period includes an interval of average value of
intensity of radiation which is characteristic of at least one
constituent of the material of said coatings.
Description
CROSS-REFERENCE TO RELATED CASES
[0001] This application is a continuation of the application Serial
No. PCT/EP 02/13339 which was filed on Nov. 27, 2002 and which
claims the priority of commonly owned German patent application
Serial No. 101 60 235.9 filed Dec. 7, 2001.
[0002] The disclosures of the PCT and German patent applications,
as well as those of all US and foreign patents and/or patent
applications identified in the specification of the present
application, are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0003] The present invention relates to improvements in methods of
and in apparatus for ascertaining one or more parameters or
characteristics of paper or the like, especially paper which is
utilized for the confinement of tobacco, filter material for
tobacco smoke, inner and/or outer wrapping material for arrays of
cigarettes and/or other smokers' products and the like. More
particularly, the invention relates to improvements in methods of
and apparatus for monitoring paper (hereinafter frequently or
mostly referred to as cigarette paper) which involve the steps of
and the means for directing electromagnetic radiation from at least
one suitable source against one side of the paper at a given angle
of incidence, measuring (e.g., with a suitable detector) radiation
issuing at the other side of the paper, and ascertaining or
determining (e.g., with an evaluation unit) the characteristics of
the paper on the basis of the measured radiation.
[0004] U.S. Pat. No. 6,130,438 (granted Oct. 10, 2000 to Torai for
"WRAPPING PAPER DETECT INSPECTION APPARATUS FOR A CIGARETTE
MANUFACTURING MACHINE") discloses a cigarette making machine
employing an optical system which causes radiation to penetrate
through cigarette paper, which evaluates the results of such
penetration, and which discards cigarettes having unsatisfactory
wrappers. The optical system of this patented arrangement employs
lasers which confront suitable photodiodes. The cigarette paper is
caused to advance between the diodes. The marginal portions of the
cigarette paper are not monitored or must be monitored by an
auxiliary system.
[0005] U.S. Pat. No. 6,020,969 (granted Feb. 1, 2000 to Struckhoff
et al. for "CIGARETTE MAKING MACHINE INCLUDING BAND INSPECTION" and
corresponding to WO 99/02051 and EP 1 011 351 A1) discloses a
cigarette making system employing a sensor which is arranged to
detect strips in cigarette paper, to detect defects in cigarette
paper and to eject (segregate) defective cigarettes. The method
which is disclosed in this US patent is based on the principle that
infrared radiation issuing from a light emitting diode is reflected
by the surface of cigarette paper and the thus reflected light is
detected by a radiation-sensitive receiver.
[0006] U.S. Pat. No. 4,845,374 (granted Jul. 4, 1989 to White et
al. for "METHOD AND APPARATUS FOR DETECTING THE DEPOSITION OF AN
ADHESIVE ON A TRAVELLING WEB") discloses a method and an apparatus
which are designed to ascertain the width of an adhesive strip on
an advancing cigarette paper web by resorting to a radiation
reflecting arrangement. The radiation issues from a fluorescent
tube and is oriented upon the web at a certain angle to a plane
which is normal to the paper web; such radiation is reflected by
the cigarette paper web to impinge, at a certain angle to the
aforementioned plane, upon and to be evaluated by a charge coupled
detector device (CCD).
[0007] German patent No. 20 43 876 discloses an arrangement which
is designed to, detect defects in transparent webs or strips and
employs a position vector consisting of polarized light and serving
to scan the web. The web is located in front of a light receiving
arrangement when the defective portions of the web, which rotate
the polarization plane, rotate the polarization is plane of the
light.
OBJECTS OF THE INVENTION
[0008] An important object of the instant invention is to provide a
method of ascertaining the characteristics of cigarette paper or
the like with a degree of accuracy, reliability and reproducibility
which greatly exceeds such parameters of presently known
methods.
[0009] Another object of this invention is to provide a relatively
simple and compact and relatively inexpensive apparatus which can
be utilized for the practice of the improved method and can be
installed in or utilized in conjunction with presently known
machines for the making, processing, wrapping, packing and/or
otherwise manipulating smokers' products including plain and filter
cigarettes or the like, packets for groups of rod-shaped smokers'
products and/or analogous commodities.
[0010] A further object of the instant invention is to facilitate
reliable segregation of defective products from acceptable products
in mass producing machines such as modern cigarette, cigarillo or
cigar making and packing machines.
[0011] An additional object of the invention is to reduce the
number of rejects which are turned out by the machines for the
making and/or processing of smokers' products and the like.
[0012] Still another object of the present invention is to take
advantage of certain characteristics of cigarette paper or the like
in order to enhance the reliability of detection of defects in
cigarette paper and/or in material(s) or substance(s) which is(are)
carried by cigarette paper during the making, packing and/or other
processing of smokers' products.
SUMMARY OF THE INVENTION
[0013] One feature of the present invention resides in the
provision of a method of ascertaining at least one parameter or
characteristic of paper, especially cigarette paper. The improved
method comprises the steps of directing against one side of the
ciparatte paper at least one beam or ray of electromagnetic
radiation (such as that furnished by a laser) at an incidence angle
a which, in accordance with an important feature of the present
invention, is between 0.degree. and 75.degree. whereby a. portion
of such radiation issues from and at the other side of a cigarette
paper, measuring the issuing radiation and ascertaining at least
one parameter or characteristic as a function of (e.g., on the
basis of) said issuing radiation.
[0014] The angle .alpha. can be in the range of between about
5.degree. and 45.degree., e.g., between about 10.degree. and
20.degree., and can often equal or approximate 15.degree..
[0015] That portion of radiation which issues from and at the other
side of the cigarette paper can also make a predetermined angle
.beta. with the other side of the cigarette paper. The angle .beta.
is between about 45.degree. and 90.degree., often preferably
between about 70.degree. and 90.degree..
[0016] It is preferred to resort to electromagnetic radiation which
has a predetermined polarized condition.
[0017] In accordance with a presently preferred embodiment of the
improved method, the electromagnetic radiation is linearly
polarized parallel to the one side of the cigarette paper.
[0018] The improved method can further comprise the step of
advancing the cigarette paper in a predetermined direction
(lengthwise), and the at least one parameter can involve the
presence or absence of essentially periodical coatings or layers
provided at least at one side of the running web of cigarette
paper; such coatings or layers entail essentially periodical
changes of intensity of radiation which issues from the web of
cigarette paper at the locus of impingement of electromagnetic
radiation against the one side of th advancing web.
[0019] The determining step of the just outlined method can include
determining the periods of changes of radiation, and the
ascertaining step includes or can include comparing the determined
periods of radiation changes with a predetermined period. Such
method can further comprise the step of ascertaining the extent of
radiation changes, and the predetermined period can include an
interval of average value of intensity of radiation which is
characteristic of at least one constituent of the material of the
coating or layer.
[0020] Another feature of the instant invention resides in the
provision of an apparatus for ascertaining at least one parameter
or characteristic of paper, such as cigarette paper. The improved
method comprises a source of electromagnetic radiation, means for
directing a beam of radiation from the source against one side of
the paper at an angle .alpha. of between about 0.degree. and
75.degree. whereby a portion of such radiation issues from and at
the other side of the paper, detector means which is arranged to
measure the issuing radiation, and means for ascertaining the at
least one parameter of paper as a function of said issuing
radiation.
[0021] The angle .alpha. can be between about 5.degree. and
45.degree., often preferably between about 10.degree. and
20.degree., and often at least close to about 15.degree..
[0022] It is normally preferred to ensure that the
[0023] radiation issuing from the other side of the paper makes
with the paper a predetermined angle .beta., and the detector means
is or can be positioned to intercept the radiation issuing at such
angle .beta..
[0024] The angle .beta. can be between 45.degree. and 90.degree.,
often preferably between about 70.degree. and 90.degree..
[0025] The improved apparatus can further comprise means for
polarizing the radiation which issues from the source before the
radiation reaches the paper. Such polarizing means can be arranged
to polarize the radiation issuing from the source in parallel to
the one side of the paper.
[0026] The improved apparatus preferably further comprises means
(e.g., one or more rollers or drums) for advancing the paper along
a predetermined path, and the detector means can be arranged to
monitor the intensity of radiation which issues from the paper. The
at least one parameter can include the presence of essentially
periodical coatings or layers provided at least at one side of the
paper in the path and entailing essentially periodical changes of
intensity of radiation which reaches the detector means subsequent
to penetration through the web in a predetermined portion of the
path. The ascertaining means of such apparatus can comprise a
memory which is operatively associated with the is detector means
and is arranged to store a predetermined period of changes for
comparison with those changes which are represented by the
radiation determined by the detector means. The memory can include
a table which denotes the extent of changes of radiation, and the
predetermined period can include an interval of average value of
intensity of radiation which is characteristic of at least one
constituent of the material of the coatings.
[0027] The novel features which are considered as characteristic of
the invention are se forth in particular in the appended claims.
The improved apparatus itself, however, both as to its construction
and the modes of assembling, installing and operating the same,
together with numerous additional important and advantageous
features and attributes thereof, will be best understood upon
perusal of the following detailed description of certain presently
preferred specific embodiments with reference to the accompanying
drawing.
BRIEF DESCRIPTION OF THE DRAWING
[0028] FIG. 1 is a somewhat schematic perspective view of a
cigarette making machine employing an apparatus which embodies the
present invention;
[0029] FIG. 2 is a diagrammatic view of one embodiment of the
apparatus which can be employed in the cigarette making machine of
FIG. 1; and
[0030] FIG. 3 is a diagram wherein the intensity of radiation
penetrating through a travelling web of cigarette paper is measured
along the ordinate and the time is measured along the abscissa.
DESCRIPTION OF PREFERRED EMBODIMENTS
[0031] FIG. 1 illustrates certain relevant details od a cigarette
rod making machine which can be of the type known as PROTOS
distributed by the assignee of the present application. This
machine comprises a gate 1 which is arranged to supply batches of
shredded and/or otherwise comminuted tobacco leaves into a
preliminary distributor 2. A tobacco withdrawing drum 3 serves to
draw tobacco particles from the distributor 2 into a magazine 4 in
such a way that the supply of tobacco in the latter is or can be
maintained at an at least substantially constant level. A
preferably automatically controlled elevator conveyor 5 of known
design (see, for example, commonly owned U.S. Pat. No. 5,072,742
granted Dec. 17, 1991 to Heitmann for "METHOD OF AND APPARATUS FOR
MAKING A FILLER OF SAMOKABLE MATERIAL") is provided to draw batches
of tobacco particles from the magazine 4 and to deliver successive
batches into a gathering duct 6 which is installed in the machine
frame at a level above a rotary carded drum 7 cooperating with a
rapidly rotating so-called picker roller 8 to propel an at least
substantially uniform stream of tobacco particles onto the upper
reach of a continuously driven constant-speed endless belt conveyor
9.
[0032] The conveyor 9 gathers and advances lengthwise a continuous
stream of tobacco particles, and the leader of such stream is
propelled against a pneumatic sifter 11 which includes nozzles
and/or analogous air discharging and directing devices forming an
upright air curtain which is traversed by larger (heavier) tobacco
particles but intercepts the lighter particles of the stream being
supplied by the belt conveyor 9. The intercepted lighter tobacco
particles descend onto the carding of a rotary drum 12 cooperating
with a wall 13 to form therewith a funnel 14. The heavier (more
satisfactory) tobacco particles which have traversed the air
curtain formed by the sifter 11 are propelled by the carding of the
drum 12 to enter a channel 16 and to impinge upon and be entrained
by the lower reach of a foraminous band conveyor 17. The latter
coperates with a suction chamber 18 to attract and advance
successive increments of a shower of satisfactory tobacco particles
toward a stream trimming or equalizing device 19.
[0033] The equalizing device 19 removes the surplus of tobacco from
the stream at the underside of the lower reach of the band conveyor
17 which conveys the thus trimmed stream onto the upper side of a
continuously advancing strip or web 21 of cigarette paper or other
suitable wrapping material. This web is drawn off a bobbin 22 and
moves in the same direction as the lower reach of the band conveyor
17 to advance the equalized tobacco stream into a wrapping
mechanism 26 employing a driven endless belt or band 24 known as
garniture. Prior to entering the wrapping mechanism 26 including
the garniture 24, successive increments of the cigarette paper web
21 advance through a printer 23 which provides successive
spaced-apart portions of the web with suitable printed matter
(e.g., the trademark(s) of the manufacturer of plain or filter
cigarettes).
[0034] The garniture 24 drapes the running web 21 of cigarette
paper around the trimmed or equalized tobacco stream (called
filler) in such a way that one longitudinal marginal portion of the
web extends substantially tangentially of and away from the
cylindrical envelope surrounding the confined tobacco stream. The
wrapping mechanism 26 further comprises a so-called paster (not
shown) which coats one side of the aforementioned one marginal
portion of the web 21 with a suitable adhesive, and such marginal
portion is thereupon folded over the adjacent portion of the thus
finished tubular envelope for the confined equalized tobacco stream
or filler of the resulting cigarette rod 28. A plate-like drying
device (e.g., a so-called tandem sealer) 27 is provided to promote
the setting of adhesive and to thus prevent the envelope from
bursting open at the adhesive-coated seam during further processing
of the continuous cigarette rod 28.
[0035] Subsequent to leaving the printer 23 but prior to reaching
the garniture 24, the web 21 advances through an apparatus 20 which
embodies one presently preferred form of the instant invention. The
purpose of the apparatus 20 is to ascertain whether or not the web
21 carries a coating or layer. The details of the apparatus 20 will
be described in greater detail with reference to FIGS. 2 and 3.
[0036] The rod 28 is caused to advance through a measuring and
regulating apparatus 29 on its way to a severing apparatus 31
(known as cutoff) which repeatedly cuts across the advancing rod to
convert the latter into a is series of successive plain cigarettes
32 of double unit length. Such plain cigarettes advance into the
range of controlled orbiting arms 33 of a transfer unit 34 which
delivers the cigarettes 32 onto a drum-shaped receiving conveyor 36
of a filter cigarette making machine 37. The latter comprises a
severing device including a drum 38 and a circular knife (not
shown) which cooperates with the drum 38 to halve each cigarette 32
into a pair of plain cigarettes of unit length. The filter
cigarette making machine 37 can be of the type disclosed in
commonly owned U.S. Pat. No. 5,135,008 granted Aug. 4, 1992 to
Oesterling et al. for "METHOD OF AND APPARATUS FOR MAKING FILTER
CIGARETTES".
[0037] FIG. 1 further shows two endless belt conveyors 39, 41 which
serve to convey surplus tobacco (removed by the trimming device 19)
back into the range of the elevator conveyor 5 which supplies such
material into the gathering duct 6. More specifically, the conveyor
41 delivers surplus tobacco into a receptacle 42 which is adjacent
the path of movement of spaced-apart paddles at the outer side of
the endless flexible element of the elevator conveyor 5.
[0038] The aforementioned regulating apparatus 29 of the continuous
cigarette rod making machine of FIG. 1 serves to control the
operation of the equalizing device. The details of such apparatus
are fully disclosed in the commonly owned copending U.S. patent
application Ser. No. 10/850,119 filed May 21, 2004 by Andreas Noack
for "APPARATUS FOR ASCERTAINING THE TRANSVERSE DIMENSIONS OF
ROD-SHAPED ARTICLES".
[0039] FIG. 2 is a diagrammatic view of the apparatus 20. This
apparatus is arranged to direct radiation from a source 40 against
one side (42) of the running web 21 and to monitor that percentage
or share of radiation which has penetrated through successive
increments of the web. The radiation source 40 is assumed to
include a laser; however, it is equally within the purview of the
present invention to employ other suitable radiation sources. The
radiation 40a issuing from the source 40 is focussed by a lens 41
having an optical axis 40b. The locus of impingement of the
focussed radiation 40a upon successive increments of the respective
side (the underside 42 in FIG. 2) of the advancing web 21 is shown
at 50. A polarizing filter 44 is interposed between the focussing
lens 41 and the locus 50. The purpose of the filter 44 is to effect
linear polarization of the radiation 40a in parallel to the surface
42 of the web 21.
[0040] The optical axis 40b makes an angle .alpha.=15.degree. with
the respective surface (underside in FIG. 2) of the travelling web
21. The illustrated angle .alpha. is but one of numerous suitable
angles (e.g., the angle .alpha. can exceed 0.degree. and can be
less than 75.degree.).
[0041] FIG. 2 shows that the underside 42 of the web 21 is provided
with a series of coatings or layers including that shown at 46. It
is also possible to turn the advancing web 21 in such a way that
the polarized radiation 40a is directed against the uncoated side
48 of the web.
[0042] The illustrated coating 46 consists of discrete paper strips
52 which extend transversely of the web 21 at selected distances
from each other. In lieu of employing coatings 52 which constitute
paper webs, it is also possible to employ other types of coatings,
e.g., silicate.
[0043] The web 21 is advanced lengthwise (in a direction to the
right, as viewed in FIG. 2) at a speed v. FIG. 2 shows the web 2 in
a position in which the radiation 40a (at the locus 50) impinges
upon one of the coatings 52.
[0044] FIG. 2 further shows a detector 54 which constitutes a
photosensitive element and is disposed at the upper side of the
advancing web 21. The detector 54 is disposed in the path of
radiation 58 which has penetrated through the web 21 and the
coating or strip 52 at the locus 50 and is focussed by a lens 56
having an optical axis 57 making with the plane of the path for the
web 21 an angle .beta.=85.degree.. The purpose of the detector 54
is to ascertain the intensity of radiation which has penetrated
through the running web 21. The angle .beta. can vary between
45.degree. and 90.degree..
[0045] The intensity I of radiation (see FIG. 3) which reaches the
detector 54 depends upon the presence or absence of a coating 52 at
the locus 50 of impingement of radiation 40a upon the web 21. Thus,
the intensity I is less pronounced if the radiation 40a must
penetrate through the web 21 as well as through one of the coatings
52 The detector 54 is designed to transmit variable-intensity
electric signals 60 to an evaluating circuit 62. The amplitudes a
of the electric signals 60 being transmitted by the detector 54 to
the evaluating circuit 62 are shown in FIG. 3. The intensity I of
such signals 60 decreases periodically, namely when the radiation
40a impinges upon a coating 52 at the locus or station 50.
Otherwise stated, the amplitude of a signal 60 which is generated
when the radiation 40a penetrates solely through the web 21 is
higher than the amplitude of that signal 60 which is obtained when
the radiation 40a is compelled to pass through the web 21 as well
as through one of the coatings 52.
[0046] The evaluating circuit 62 can embody a memory for the
storage of a given timing or period of changes of intensity I, and
such memorized periods can be compared with the intervals of
variations of intensity I which are attributable to the frequency
of arrival of successive coatings 52 at the station or locus
50.
[0047] It is also possible to associate the evaluating circuit 62
with a memory for the storage of a table which embodies information
denoting at least one extent of change of intensity I attributable
to a particular material (such as cellulose) in the coating 46. The
evaluating circuit 62 embodying or associated with such table can
be designed to furnish information denoting an average value of
intensities I within a preselected interval of time t, to furnish
information denoting the actual extent a of changes relative to an
average value and to ascertain--with reference to the
aforementioned stored table--the nature of material (e.g.,
cellulose) of which the coatings 46 consist. This is possible
because different coatings cause more or less pronounced changes of
intensity I.
[0048] The polarizing (at 44) of radiation 40a enhances the changes
a in comparison with an irradiation of cigarette paper with
non-polarized light.
[0049] An important advantage of the improved method and apparatus
is that they can be resorted to for a highly reliable ascertaining
of one or more selected characteristics of cigarette paper or the
like, e.g., the aforediscussed and illustrated presence or absence
of coatings or layers 46 as well as the material(s) of such layers.
This can be accomplished without it being necessary that the angle
.alpha. match the angle .beta.. An advantage of a method and
apparatus wherein the angle .alpha. need not match the angle .beta.
is that highly accurate results can be achieved without the need
for extensive adjustments of the optical, monitoring and evaluating
systems.
[0050] As already mentioned hereinbefore, the invention is based on
the recognition that the reflection coefficient of coated portions
of, cigarette paper is higher than that of the uncoated portions,
i.e., the quantity of radiation penetrating through coated portions
of a running cigarette paper web is below that which can penetrate
through uncoated portions. The utilization of radiation-polarizing
means (such as the polarizing filter 44 shown in FIG. 2) enhances
the contrast between the coated and uncoated portions of the web
21. Especially if the radiation is linearly polarized parallel to
the respective surface or side (42 in FIG. 2) of cigarette paper,
the contrast between the irradiated and non-irradiated portions of
the web is even more pronounced. Thus, if the running web 21 is
irradiated at one (42) of its sides with linearly polarized light
issuing from the source 40 or an equivalent thereof, the presence
or absence of coatings or layers 46 can be detected with a high
degree of accuracy by evaluating the radiation 58 which issues at
the other (non-irradiated) side of the running web 21.
[0051] The feature that the radiation source 40 can be installed at
either of the two sides (42, 48) of the cigarette paper web 21
brings about the advantage that the improved apparatus 20 can be
readily installed at an available location in a cigarette making
machine or in any other machine wherein a web of paper or the like
(such as cigarette paper) is to be examined for the presence or
absence of coatings 46 or the like
[0052] As also already mentioned hereinbefore, the coatings or
layers 46 can consist of cellulose or silicate. Such coatings can
be utilized as so-called combustion or burning stops which serve to
ensure the extinguishment of a cigarette which was unintentionally
left in lighted condition for an excessive interval of time. The
reason is that, due to the composition of the coatings 46, the
respective portions of cigarette paper 21 permit the penetration of
lesser quantities of atmospheric air into the tobacco filler of the
lighted cigarette. In other words, such coatings effect a reliable
extinguishment of a lighted cigarette and thus greatly reduce the
likelihood of accidental fires.
[0053] It has been ascertained that the contrast between the
intensities of radiation penetrating through the coated and
uncoated portions of a cigarette paper web 21 is especially
satisfactory if the angle .alpha. matches or approximates
15.degree.. By the same token, it is advisable to select a
particular angle .beta. (preferably between about 70.degree. and
90.degree.) because this also contributes to a more pronounced
contrast between penetrations of the radiation through coated and
uncoated portions of the running web 21. Such contrast, too, can be
enhanced if the radiation 40a is linearly polarized parallel to the
plane of the cigarette paper web 21 in its path.
[0054] In the machine of FIG. 1, the means for advancing the web 21
lengthwise along the path extending between the polarizing filter
44 and the focussing lens 56 includes the garniture 24. It will be
appreciated that other forms of web advancing means can be employed
with equal or similar advantage.
[0055] Without further analysis, the foregoing will so fully reveal
the gist of the present invention that others can, by applying
current knowledge, readily adapt it for various applications
without omitting features that, from the standpoint of prior art,
fairly constitute essential characteristics of the generic and
specific aspects of the above outlined contribution to the art of
ascertaining selected parameters of cigarette paper or the like
and, therefore, such adaptations should and are intended to be
comprehended within the meaning and range of equivalence of the
appended claims.
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