EP1036003B1 - Method for checking that batches of cigarettes are complete and that the cigarettes are sufficiently filled - Google Patents

Description

The invention relates a method for checking orderly, the contents of a pack of cigarettes Cigarette groups with one with signal processing connected electro-optical test device, preferably a CCD line chip or a CCD camera, for measuring the intensity light reflected by preferably filter-side end faces of the cigarettes, wherein a measurement field preferably formed from pixels of the test organ assigned to at least one partial area of the end faces of the cigarettes is.

For the production of cigarettes and the filling of cigarette groups There are high-performance machines in cigarette packs required. Despite careful manufacturing, it does happen again and again that the created and to the. Delivered to customers Cigarette packs of missing or insufficient cigarettes Have cigarettes filled with tobacco. In selecting of test methods for sorting out such defective cigarette groups it should be noted that the examination is carried out quickly, continuous or discontinuous funding process take place got to.

In a previously used test method, an orderly, the cigarette group corresponding to the content of a cigarette packet moved past a test facility in which the by intensities of reflected light measured by a CCD camera can be statistically evaluated. This procedure and corresponding Arrangements are described in US-A-4,486,098 or US-A-4,511,045.

DE 40 00 658 describes a method for checking the ends of Cigarettes of a cigarette group known by optical means. The cigarette ends are illuminated and the picture taken is being processed. The brightness values become more individual Pixel examined. The number of pixels with the same brightness is added and plotted in a coordinate system to form a histogram. There are three characteristic in this histogram Maxima. The number of pixels belonging to one of the maxima then counted. If the number of pixels within this maximum predetermined limits, the respective cigarette is considered evaluated correctly and the next cigarette examined.

The invention has for its object an improved, contactless working test procedure to check the completeness of cigarette groups and / or the filling of the Propose tobacco cigarettes.

The method according to the invention is used to achieve this object according to claim 1 or Claim 3 Proposed.

The measuring device for checking the cigarette groups thus works non-contact based on a CCD line chip or one CCD camera, so that an examination of the cigarette group also fast funding cycle is possible. Here, the measuring element can any place in the funding process, as long as in this the front sides of the cigarette groups are freely accessible are. For example, the exam during funding in a pocket conveyor. One more way is the examination of the cigarette groups in a folding turret.

at the evaluation of the from the CCD camera or the CCD line chips delivered intensity curve from a count of the passes of the intensity curve by a threshold with subsequent over and / or The number of cigarettes is below the threshold determined in the area of the evaluation bar (s). This evaluation method is based on the fact that the reflected Light in the area of the bright filter surfaces of the cigarettes is larger is considered the intensity in the area of dark, from neighboring Cigarettes formed cigarette spaces measured becomes. An increase in the measured intensity curve can therefore as a transition from a cigarette space to a filter side Front of a cigarette can be evaluated. At the The absence of a cigarette in a row of cigarettes will high intensity in the area of the filter surfaces even less achieved than with a complete line of cigarettes. This is based on the count of the passes of the intensity curve detected by a threshold.

In the absence of a cigarette within a cigarette group with several rows of cigarettes, neighboring cigarettes shift. As a result, the distance between the first and last cigarette in a row due to the lack of one Cigarette is decreased. Another according to the invention The method is therefore characterized in that from the comparison the distance between the first and last pass of the intensity curve by a threshold with a setpoint the completeness of the cigarette group is determined.

With the number of filter-side end faces of the cigarettes in the Area of the evaluation bar of the CCD line chip or the CCD camera the number of high measured intensity values increases. In a further method according to the invention can accordingly in particular by adding up the along the evaluation bar measured intensity values determined, area below the Curve of the measured intensity signal with one for the complete Cigarette group determined target value are compared.

Will be beneficial one in the front assigned to the cigarettes and the spaces between the cigarettes Measurement signal measured according to the horizontal and vertical positions of the pixels as a two-dimensional measuring field evaluated.

In a three-dimensional representation of the measured intensity above the horizontal and vertical position of the pixels in the two-dimensional measuring field is the intensity curve as curved surface can be represented, the high plateaus in the area lighter Has cigarette surfaces, for example in the area of bright end faces of the cigarettes, and valleys for the areas with low measurement intensities, for example in the range of Cigarette interspaces.

This relief-like is preferred Change of mountains with high plateaus and valleys evaluated in such a way that when the measuring field is arranged on the tobacco side, the presence a large number of small neighboring intensity values as an indicator for recesses in the filling of the cigarettes is used with tobacco. With this test method is thus targeted for valleys, i.e. flat areas small neighboring intensity values. In the area of a So there is a flat shadow area on the tobacco side Front of the cigarette. This can be used as an indicator for recesses in the filling of the cigarettes, so-called Blowholes, are rated.

In the absence of a cigarette from a cigarette group and in the Checking the cigarettes in the area of the filter-side end faces of cigarettes results in the absence of a cigarette from the cigarette group to that in the area where for a complete Cigarette group a plateau with high intensity should have a "valley" with low measurement intensities. In the area of the target positions of the front filter surfaces is therefore in place of many neighboring high measurement intensities measured a large number of low measurement intensities. In the Determination of the frequency distribution of the measured values with measuring intensities within predefined intensity classes the occurrence of a high frequency with high measurement intensities to the presence of a light filter surface while the presence of large frequencies with small measurement intensities evaluated as an indicator for a dark space between cigarettes can be.

Further methods relate to preferred configurations of the invention.

Fig. 1

Fördereinrichtung für Weichbecherpackungen in Seitenansicht,

Fig. 2

Prüfeinrichtung zur Prüfung von Zigarettengruppen in Draufsicht,

Fig. 3

fehlerhafte Zigarettengruppe in der Tasche eines Taschenförderers,

Fig. 4

horizontale und vertikale Auswertebalken zum Prüfen einer Zigarettengruppe,

Fig. 5

Beispiel eines gemessenen Intensitätssignals entlang eines horizontalen Auswertebalkens,

Fig. 6

Beispiel eines gemessenen Intensitätssignals entlang eines vertikalen Auswertebalkens,

Fig. 7

Meßbereiche des Prüfverfahrens im Filterbereich und im Bereich der Zigarettenzwischenräume,

Fig. 8

Häufigkeitsverteilung gemessener Intensitäten im Filterbereich,

Fig. 9

Häufigkeitsverteilung gemessener Intensitäten im Bereich der Zigarettenzwischenräume,

Fig. 10

Meßergebnis der CCD-Kamera, gemessen auf der tabakseitigen Stirnseite im Bereich einer korrekt befüllten Zigarettengruppe,

Fig. 11

Meßergebnis der CCD-Kamera, gemessen auf der tabakseitigen Stirnseite im Bereich einer fehlerhaft befüllten Zigarettengruppe,

Fig. 12

dreidimensionale Darstellung des Intensitätsverlaufs,

Fig. 13

Blockschaltbild der Meßsteuerung und Signaldatenverarbeitung zur Kontrolle der Vollständigkeit und Befüllung der Zigarettengruppe.

Further details of the method are explained in more detail below on the basis of the exemplary embodiments illustrated in the drawings. It shows:

Fig. 1

Conveying device for soft cup packs in side view,

Fig. 2

Test device for testing cigarette groups in top view,

Fig. 3

faulty cigarette group in the pocket of a pocket conveyor,

Fig. 4

horizontal and vertical evaluation bars for checking a cigarette group,

Fig. 5

Example of a measured intensity signal along a horizontal evaluation bar,

Fig. 6

Example of a measured intensity signal along a vertical evaluation bar,

Fig. 7

Measuring ranges of the test method in the filter area and in the area of the cigarette spaces,

Fig. 8

Frequency distribution of measured intensities in the filter area,

Fig. 9

Frequency distribution of measured intensities in the area of the cigarette spaces,

Fig. 10

Measurement result of the CCD camera, measured on the tobacco-side end in the area of a correctly filled cigarette group,

Fig. 11

Measurement result of the CCD camera, measured on the tobacco-side end face in the area of an incorrectly filled cigarette group,

Fig. 12

three-dimensional representation of the intensity curve,

Fig. 13

Block diagram of the measurement control and signal data processing for checking the completeness and filling of the cigarette group.

The details shown in the drawings relate a preferred application example, namely manufacturing of soft cigarette pack type cigarette packs. FIG. 1 shows the basic concept of a packaging machine 10 for the Production of such cigarette packs 11. The cigarettes the packaging machine 10 in the area of a cigarette magazine 12 passed. This is a packaging machine 10 Organ used for storing cigarettes of cigarettes and for the delivery of cigarette groups 13 corresponding to the content of a cigarette packet 11. The cigarette magazine For this purpose, 12 is in the lower area with magazine shafts 14 provided that summarized as shaft groups are. Each shaft group becomes a cigarette group 13 by slide out and in pockets 15 of a pocket chain 16 inserted, in the region of a lower conveyor run 17.

The pocket chain 16 transports the cigarette groups 13 a folding turret 18 to which it can be pushed out of the pockets 15 of the pocket chain. 16 are handed over. details about the structure of the cigarette magazine 12, the pocket chain 16 and the folding turret 18 result from EP 226 872.

At the position marked with the arrow A or B in the conveying flow, namely in the area of the lower conveyor run 17 or in Folding turret 18, the cigarette groups 13 through the inventive Test procedures for completeness or completeness the filling of the cigarettes checked. The testing facility 19 an ejector 20 is arranged downstream in the conveying direction, that in the event of an error signal from the test device 19 for rejection defective cigarette groups 13 is operated.

The test device preferably has a test device 20 CCD line chip or a CCD camera. The test organ 21 is an optics 22 upstream. Another component of the test facility are, for example, two light sources 23, which are preferred at an angle of 5 to 15 ° to the shooting direction of the test element 21 are inclined. Test organ 21 and assigned Light sources 23 are aligned such that the an end face 24 of the cigarette packet 11 reflects light of the light sources 23 is detected by the test device 21. The light source 23, preferably a light source of high intensity or a laser, can be stroboscopic to the beat of the machine can be controlled. In the embodiment shown in Fig. 2 is a test device 19 on the filter side End face 24 of the cigarette packs 11 arranged. Find here for example a completeness check of the cigarette group instead of. Another test facility is on the tobacco side End face 24 of a cigarette group 13 arranged. With this, for example, the complete filling of individual Cigarettes 25 can be checked, but is possible here also the simultaneous control of the completeness of the cigarette group 13 and the filling of the cigarettes 25 with tobacco.

3 shows the filter-side end face 24 of a cigarette group 13 and a pocket assigned to the cigarette group 13 15 of the pocket chain 16. On the pocket 16 there are vertical ones Mark 26 and a horizontal mark 27 for alignment the image of the test device 21 is provided. With a vertical Moving the pocket 15 becomes the horizontal mark 27 vertically shifted with a slight time delay when recording an intensity curve 28 through the Test organ 21, that is the CCD camera or the CCD line chip the vertical marking 26 laterally in the recorded image their target position shifted. The one captured by the CCD camera Image is based on the markings in the coordinate system of the Evaluation unit aligned.

• die strichpunktierten Kreise 33 markieren die Sollpositionen der Zigaretten in der Zigarettengruppe,
• die Kreisflächen mit durchgezogener Umrandung 34 sind Teilflächen der Zigarettenstirnseite, deren Bedeutung für das Auswerteverfahren im folgenden dargestellt wird,
• weitere Auswerteflächen sind die mit schwarzen Kreisflächen markierten Schattenflächen 35 im Bereich der Zigarettenzwischenräume 36,
• in Fig. 4 sind mit horizontalen Linien horizontale Auswertebalken 37 markiert, die vorzugsweise derart verlaufen, daß ein Auswertebalken sowohl den Bereich der Sollposition jeder Zigarette 33 einer Zigarettenreihe 29 oder 30 als auch einen Schattenbereich 35 im Bereich zweier benachbarter Zigaretten einer Zigarettenreihe 29 oder 30 durchläuft,
• vertikale Auswertebalken 38 sind vorzugsweise derart angeordnet, daß in vertikaler Richtung die Zigarettenzwischenräume 36 zwischen Zigaretten benachbarter Zigarettenreihen durchlaufen werden.

A complete cigarette group 13 has, for example, seven cigarettes 25 in each outer, horizontal row of cigarettes 29, and the inner horizontal row of cigarettes 30 contains six cigarettes. The cigarette group 13 shown is thus a missing group. As a result of a missing cigarette in the inner row of cigarettes 30, two cigarettes 31 and 32 of the outer rows of cigarettes 29 have been shifted from the desired positions into the interior of the pocket 15. Such fault groups are separated using the following measuring ranges:

• the dash-dotted circles 33 mark the desired positions of the cigarettes in the cigarette group,
• the circular areas with solid border 34 are partial areas of the cigarette front side, the meaning of which for the evaluation method is shown below,
• further evaluation areas are the shadow areas 35 marked with black circular areas in the area of the cigarette spaces 36,
• In Fig. 4, horizontal evaluation bars 37 are marked with horizontal lines, which preferably run in such a way that an evaluation bar passes through both the area of the target position of each cigarette 33 of a row of cigarettes 29 or 30 and a shadow area 35 in the area of two adjacent cigarettes of a row of cigarettes 29 or 30 .
• vertical evaluation bars 38 are preferably arranged such that the cigarette spaces 36 between cigarettes of adjacent rows of cigarettes are traversed in the vertical direction.

The circular areas 34 and shadow areas 35 can of course also a contour that deviates from the circular shape shown exhibit.

For determining the completeness of a row of cigarettes 29, 30 is the reflected along a horizontal evaluation bar 37 Light intensity measured with a test organ 21. To do this the evaluation bar 37 through several pixels of the CCD line chip or the CCD camera. Each pixel records the Light intensity of a section of the evaluation bar 37. In 5 is the horizontal evaluation bar 37 by 230 pixels in 230 sections of the same size divided. The illustrated Measurement signal 39 represents the measured intensity for pixels 0 to 229. The light intensity is usually in the unit Candela stated. Through the CCD camera, the intensity converted into a proportional measurement signal at the measurement location, for example into a tension. For this reason, the measurements are for the intensities given below without units. The absolute values of the measured values are in the following text square brackets.

The intensity of the reflected light is large in the range the assigned to the (light) end faces 24 or filters of the cigarettes Pixels, see high intensity plateaus 40 in Fig. 5. In the area of the shadow areas 35 between the Pixels assigned to cigarettes 25 break the intensity. With dash-dotted line here is the measured error signal 41 shown in case of a missing cigarette.

The method for evaluating the measurement signal 39 can, for example the passages 42 of the measurement signal through a threshold value Count 43. In the example shown, the measurement signal runs through 39 seven times the threshold value 43 in positive or negative Direction. So there are seven cigarettes in the row of cigarettes 29, 30.

Another method determines the area below that in FIG. 5 shown measurement signal 39. This can by totaling the intensities measured from pixels 0 to 229 are determined. The deviation of a sum determined in this way from one Target value can be used as an indicator of the absence of a cigarette 25 in the row of cigarettes 29, 30, because in the range of the error signal 41 marked with a dash-dotted line as a result the missing cigarette 25 the defect area 44 under the Curve is much smaller than the comparison surface 45, so only include small values in the summation.

In another evaluation method, the vertical Evaluation bar 38 assigned intensity measured intensity evaluated, see Fig. 6. The vertical evaluation bar 38 preferably pass directly through the cigarette end faces Surroundings of the end face center 46. The two High intensity plateaus 47 shown in FIG Measurement signal 39 characterize measurements in the area of a End face 24. The edge region is between the two plateaus 47 48 of a cigarette 25 of the inner row of cigarettes 30 run through, so that here the intensity over a lower Width increases and forms a local maximum 49. Corresponding The method described above can also do this here Exceeding or falling below a threshold value 43 for evaluation be used. In a simplification of this procedure however, only the first pass 50 of the measurement signal 39 through the threshold value 43 and the last passage 51 of the measurement signal 39 evaluated by the threshold value 43. For this assigned to first pass 50 or last pass 51 The distances D1 and D2 can be determined by pixels. alternative can of course also from both sides or from above and from the first pass can be determined below (with regard to the measuring direction see also the arrows in Fig. 4).

The absence of a cigarette 25 in the cigarette group 13 has with the result that the distance of adjacent cigarettes 25 from the Side wall 52 of the pocket 15 is enlarged, see here cigarettes 31 and 32 in Fig. 3. This has an increase in the spacing D1 and D2 result. From the comparison of the sum D1 + D2 an error signal can be determined with a setpoint. Analogous this can of course also be the distance D of the first pass 50 and the last run 51 used for the evaluation become.

Problems can arise from using the test procedure described during an inspection of cigarette group 13 in the area of the folding turret 18 prepare. The cigarette groups are in the folding revolver 13 not surrounded by dark pockets 15, but by light ones Packing material. As a result, it can happen that Measurement signal 39 outside the cigarette group 13 high intensities and therefore no first and last Passage 50, 51 is present. In this case, another Procedure for determining the completeness of the cigarette group 13 are used, which on the in the partial area, namely circular surface 34 of the end face 24 and the shadow areas 35, measured intensities based. In the circular areas 24 of the filter-side end face of a cigarette are here arranged several pixels. The bright filter-side end faces 24 reflect light with a high intensity, for example Intensities between [59] and [63], see Fig. 8. For the Evaluation of those assigned in the partial areas of the end face 24 Intensities measured in pixels become several classes 54 of intensity, for example classes 54 with intensity values in the range of [59] - [60], [60] - [61] and [61] - [62]. In the measurement result shown in FIG. 8, the frequency N is the Pixels per intensity class for a measurement in the area of the filter side End face 24, the frequency 72 is applied over the intensity class 71. For more than 238 An intensity of> [60] was measured. The number is the pixel with intensities below a threshold here approximately zero if the filter-side end face 24 the cigarette 25 is in the desired position (in practice the intensity below a threshold value due to measurement inaccuracies approximately zero).

If there is no cigarette 25, move the cigarette group 13 the other cigarettes 25 of the cigarette group 13. This has the consequence that shadow areas 35 in the Move the bright filter-side target positions of the cigarettes 33. So are measured values with intensities below the Threshold 55 before, this can be an indicator of a faulty Position of one or more cigarettes 25 evaluated become. In the case of digitized intensity values, the Classes are also formed from the digitization levels, so that pixels of the same intensity are then added up.

For measurements in the shadow area 35 in the cigarette space 36 of neighboring cigarettes 25 is the intensity of the reflected Light very small, see Fig. 9. The number of Pixel is smaller here because the assigned measuring areas for the Shadow areas 35 are smaller. For a partial area of the measuring field, which is in the target area of the shadow areas 35 the number of pixels with intensities greater than a predefined one Threshold 56 zero. The displacement of the remaining cigarettes 25 from its target position 33 due to the lack of a cigarette 25 the cigarette group 13 has the result that in the target positions 33 of the shadow areas 35 bright filter areas arranged are. So there are 35 measurements for measurements in the shadow area with intensities above a threshold value 56, this can as an indicator of the incorrect position of one or more Cigarettes 25 are evaluated.

In another measuring method, a measuring surface 57 is in the area the tobacco-side end face 24 of the cigarette group 13 divided into several pixel areas 58, each one pixel is assigned to the CCD camera. Fig. 10 shows an enlargement a section of the measuring surface 57 in which each square describes pixel area 58 captured by a pixel and the latter Numerical value assigned to square that in the pixel area 58 measured brightness describes. Mark dark pixel areas 58 here areas with low intensities, so Mark dark end areas, light pixel areas 60 bright measuring surfaces.

The circular contours formed by pixels with high measurement intensities 61 correspond to the outer contour of the cigarettes 25, because the bright tobacco casing reflects light with high intensity. The intensity fluctuates within the casing very strong with medium values. This is because that the end face 24 formed by tobacco is uneven. image 10 represents the measurement result of correctly formed cigarettes 25 represents. In the area of the tobacco The face 24 of the cigarette 25 fluctuates greatly in intensity strong, but not through several neighboring pixel areas 58 large areas formed with low intensity in front. If the cigarettes are not properly filled with tobacco there are recesses from the end face of the cigarettes. These areas are formed by a plurality of pixel areas 58 Areas with low measurement intensity, cf. see picture 11, characterized. Counting the number of neighboring pixel areas 58 with intensities below a predefined one Threshold can therefore be used as an indicator of insufficiently filled Cigarettes 25 are used.

12 shows a section of the result of the intensity measurement by means of the test device, for example a CCD camera, with filter-side arrangement. Here is the Intensity 75 over the x-axis 73 and the y-axis, that is, depending from the horizontal and vertical measuring position. Here are the plateaus 61 with high intensities in the range of bright filter-side end faces 24 to recognize. Every plateau 62 is measured by the intensities of many pixels, here 500, formed. In the dark shadow areas 35 neighboring Cigarettes 25 form in the three-dimensional Representation of valleys 63. With a correctly trained cigarette group 13 are therefore 7 + 6 + 7 = 20 such Valleys 63 separate plateaus 62 before, in the absence of a cigarette 25 a plateau 62 is replaced by an additional valley 63. The volume under a measuring surface 64 created in this way is 64 depending on the number of plateaus 62. Accordingly, that Deviation of the determined volume from a target value as an indicator be evaluated for missing cigarettes 25. The investigation of the volume is proportional to the sum of the individual intensities measured in the measuring surface 64, so that the volume or a measure proportional to it in simple Way can be determined. Of course, such Evaluation procedure also on the tobacco-side end faces 24 of the cigarette group 13 are carried out, so that here Check the completeness of the cigarette group 13 and the filling the cigarettes 25 can be made with a test device 21.

Of course, to increase the security of the test procedure also used several of the test methods shown simultaneously become.

The measuring methods shown have the following block diagram 65 for signal data processing and machine control together, s. Fig. 13:

The test process is started by a trigger signal 66, which is generated, for example, by a light barrier if a new bag 15 with cigarette group 13 in the test area arrives. This trigger signal 66 becomes the image processing 67 supplied which stroboscopically a light source 23, for example a laser. Simultaneously with the flashing the cigarette group 13 is checked by means of the test device 21, for example a CCD line chip or a CCD camera Image captured and fed to image processing 67. This via a suitable I / O interface 68 of the machine control 69 fed. In addition to checking the completeness the cigarette group 13 and the filling of the cigarettes 25 with Tobacco must also monitor signal processing 70 whether the test organs 21 are ready, the image of the test organ 21 is recorded at the right time and / or the Signal quality is sufficient. For example, in the case of defective Light conditions due to a defective light source 23 Error signal are generated so that the machine stopped and the light source 23 can be replaced. The machine control 69 is also connected to an ejector 71, so that when an incomplete group of cigarettes is recognized 13 or incomplete filling of the ejectors' cigarettes 25 71 operated to remove the faulty cigarette group 13 can be. Of course, you can also or simultaneously successively controlled several separate test devices 19 and be evaluated.

LIST OF REFERENCE NUMBERS

10

packaging machine

11

cigarette pack

12

cigarette magazine

13

cigarette group

14

magazine well

15

bag

16

bag chain

17

lower funding strand

18

folding turret

19

test equipment

20

ejector

21

Review body

22

optics

23

light source

24

front

25

Cigarette

26

vertical marking

27

horizontal marking

28

intensity curve

29

outer row of cigarettes

30

inner row of cigarettes

31

Cigarette

32

Cigarette

33

Target position of the cigarette

34

circular area

35

shadow area

36

Cigarettes gap

37

horizontal evaluation bar

38

vertical evaluation bar

39

measuring signal

40

plateau

41

error signal

42

passage

43

threshold

44

error area

45

comparison area

46

Face center

47

plateau

48

border area

49

local maximum

50

first try

51

last run

52

Side wall

53

filter

54

great

55

threshold

56

threshold

57

measuring surface

58

pixel area

59

dark pixel area

60

bright pixel area

61

circular contour

62

plateau

63

valley

64

measured curve

65

Block diagram

66

trigger signal

67

image processing

68

I / O interface

69

machine control

70

Signal processing

71

intensity class

72

frequency

73

X axis

74

y-axis

75

intensity

Claims (14)

1. Method for checking ordered cigarette groups (13) corresponding to the content of a cigarette pack (11)

   where an intensity of light reflected by ends (24) of cigarettes (25) is measured by an electro-optical checking element (21), preferably a CCD linear array chip or a CCD camera, connected to a signal data processing arrangement (70), using a measurement zone formed from pixels,

   where the measurement zone is assigned to at least one partial area of the ends (24) of the cigarettes (25) and cigarette interspaces (36) formed between the latter,

   where a measurement signal is measured in the measurement zone and evaluated in the signal data processing arrangement (70), and

   where the measurement signal is measured along at least one linear, curved or rectilinear, in particular horizontal or vertical, evaluation bar (37, 38), and is evaluated in order to check whether the cigarette group (13) is complete,

   characterized in that

   either the number of cigarettes (25) in the region of the evaluation bar or bars (37, 38) is determined from a count of the crossings (42) of the measurement signal, measured along the evaluation bar, through a threshold value (43) with the threshold value (43) subsequently being exceeded and/or undershot, or

   in the case of the measurement signal measured along the evaluation bar, the completeness of the cigarette group (13) is determined from the comparison of the distance (D) between the first and last crossings of the intensity profile through the threshold value (43) with a desired value.
2. Method according to Claim 1, characterized in that the evaluation bar (37, 38) runs both in the region of desired positions of each cigarette (33) in a row (29, 30) of cigarettes in the cigarette group (13) and in a shadow region of two adjacent cigarettes in a row (29, 30) of cigarettes.
3. Method for checking ordered cigarette groups (13) corresponding to the content of a cigarette pack (11),

   where an intensity of light reflected by ends (24) of cigarettes (25) is measured by an electro-optical checking element (21), preferably a CCD linear array chip or a CCD camera, connected to a signal data processing arrangement (70), using a measurement zone formed from pixels,

   where the measurement zone is assigned to at least one partial area of the ends (24) of the cigarettes (25) and cigarette interspaces (36) formed between the latter,

   where a measurement signal is measured in the measurement zone and evaluated in the signal data processing arrangement (70),

   characterized in that

   the measurement signal is measured in partial zones of the measurement zone which are assigned to desired positions of the cigarette interspaces (36) or desired positions of partial areas (34) of individual ends (24), and is evaluated in order to check whether the cigarette group (13) is complete, and

   the measurement signal (39) measured in pixels assigned to the ends (24) of the cigarettes (25) and also to the cigarette interspaces (36) is evaluated in accordance with the horizontal and vertical positions of the pixels as a two-dimensional measurement zone and the volume formed under the two-dimensional measurement zone is used as an indicator of missing or defective cigarettes.
4. Method according to Claim 1 or 3, characterized in that the area (44, 45) underneath the measurement signal (39) is compared with a desired value determined for the complete cigarette group (13).
5. Method according to Claims 1 and 4, characterized in that, an area (44, 45) underneath the measurement signal (39) is determined by summation of measured values measured along the evaluation bar (37, 38).
6. Method according to Claim 3, characterized in that, in the case where the measurement zone is arranged on the tobacco side, the presence of a large number of small adjacent intensity values is used as an indicator of recesses in the filling of the cigarettes (25) with tobacco.
7. Method according to Claim 3, characterized in that, in the case where the measurement zone is arranged on the filter side, in the representation of the intensity against the horizontal and vertical positions of the pixel assigned to each measured value, the volume formed under the measurement curve (64) is used as an indicator of missing cigarettes (25).
8. Method according to Claim 3, characterized in that, in particular in the case where the measurement zone is arranged on the filter side, in order to determine a frequency distribution, the number of pixels with measurement intensities within predefined classes (54) of intensity is determined.
9. Method according to Claim 3 or 8, characterized in that, at the partial zones of the measurement zone which are assigned to the desired positions of the cigarette interspaces (36), the presence of excessively large or excessively small frequencies of measured values above or respectively below a threshold value (55) of the intensity is evaluated as an indicator of an incomplete cigarette group (13).
10. Method according to Claim 3 or 8, characterized in that, at the partial zones of the measurement zone which are assigned to the desired positions of the filter-side ends (24) of the cigarettes (25), the presence of excessively large or small frequencies of measured values below or respectively above a threshold value (55, 56) of the intensity is evaluated as an indicator of an incomplete cigarette group.
11. Method according to one of the preceding claims, characterized in that, if the cigarette groups (13) are incomplete, an error signal is generated which is fed to an ejector (71) arranged downstream of a checking device (19) in the conveying direction.
12. Method according to one of the preceding claims, characterized in that the measured values are recorded and processed in the machine cycle, for example in a manner initiated by a trigger signal (66) of a light barrier at the instant when a cigarette group (13) enters a checking region.
13. Method according to one of the preceding claims, characterized in that the measured values are recorded and processed by one or more measurement and evaluation devices simultaneously for at least one or more cigarette groups (13).
14. Method according to one of the preceding claims, characterized in that the evaluation bars (37, 38) or the measurement zone is oriented with the aid of markings (26, 21), preferably horizontal or vertical, arranged in the region or surroundings of the cigarette groups (13).

Images