WO2003048747A2

WO2003048747A2 - Method and device for detecting a property of a cigarette paper

Info

Publication number: WO2003048747A2
Application number: PCT/EP2002/013339
Authority: WO
Inventors: Dierk SCHRÖDER
Original assignee: Hauni Maschinenbau Aktiengesellschaft
Priority date: 2001-12-07
Filing date: 2002-11-27
Publication date: 2003-06-12
Also published as: AU2002342923A1; AU2002342923A8; EP1456625A2; WO2003048747A3; DE10160235A1; US20040216755A1

Abstract

The invention relates to a method for detecting a property of a cigarette paper (21). The inventive method comprises the following steps: one side (42) of the cigarette paper (21) is exposed to electromagnetic radiation (40a) at a given angle of incidence (α) in relation to the cigarette paper (21); the radiation (58) emerging on the other side (48) of the cigarette paper (21) is measured; and the property of the cigarette paper (21) is detected on the basis of the measured radiation (58). The invention is characterised in that the angle of incidence (α) selected is between 0° and 75°.

Description

Method and device for detecting a property of cigarette paper

The invention relates to a method for detecting a property of cigarette paper, for example a coating of the cigarette paper, in which the cigarette paper is irradiated from one side at a certain angle of incidence to the cigarette paper with electromagnetic radiation, which is measured on the other side of the cigarette paper, and the property of the cigarette paper is detected on the basis of the measured radiation. The invention further relates to a device for detecting a property of cigarette paper, with a radiation source in order to irradiate the cigarette paper with electromagnetic radiation from one side at a specific angle of incidence to the cigarette paper, with a detector to measure radiation emerging on the other side of the cigarette paper, with an evaluation circuit to detect the property of the cigarette paper based on the measured radiation. Cigarette paper is to be understood as all papers of the tobacco processing industry, for example covering paper, filter wrapping paper, inside or outside wrapping paper for cigarette packs or cigarette paper.

Such methods and devices are known from the prior art. For example, US Pat. No. 6,130,438 discloses a cigarette manufacturing machine with an optical system using the transmitted light method for detecting errors in the cigarette paper and for ejecting cigarettes produced therefrom. For this purpose, the optical system uses lasers, the corresponding photodiodes are located frontally, the cigarette paper being passed through between the diodes to be illuminated. The edge area of the cigarette paper is not detected or is detected with an auxiliary device.

WO 99/02051, which corresponds to US Pat. No. 6,020,969 and EP 1 011 351 A1, shows a system for producing cigarettes with a sensor that detects strips in the cigarette paper, detects defects in the cigarette paper and ejects the defective cigarettes. The method described in the publication works on the principle that infrared light from a light-emitting diode is reflected from the surface of the cigarette paper and is detected by a light-sensitive receiver.

From US 4,845,374 a device for determining the width of glue strips on a moving cigarette paper strip in the reflection method is known, in which light from a fluorescent tube is irradiated onto the paper at a certain angle to the paper normal, is reflected by the paper and hits a CCD detector from a certain angle to the paper normal and is detected by it.

DE 20 43 876 describes an arrangement for detecting errors in transparent webs, in which a travel beam consisting of polarized light scans the web. Arranged behind the web is a light receiving device which receives light when the polarization plane rotates defects of the web rotate the polarization plane of the light.

The object of the present invention is to improve a method and a device of the type mentioned at the outset. This object is achieved according to the invention by a method according to claim 1 and a device according to claim 12.

The advantages of the invention are, in particular, that a property of the cigarette paper, for example a coating of the cigarette paper, can be recognized without any doubt, whereas it is not necessary for an optimal quality of the measurement due to the transmitted light method used that the angle of incidence of the light beam is equal to a reflection angle of the Beam of light. In comparison to a measurement in reflection in the device according to the invention or when carrying out the method according to the invention, therefore, less adjustment effort is required for a clear measurement result.

The invention encompasses the knowledge that coated areas of cigarette paper have a higher reflection coefficient than uncoated areas, so that coated areas transmit less light than uncoated areas. The light can also be polarized. This increases the contrast between coated and uncoated areas, particularly in the case of linear polarization parallel to the surface of the cigarette paper. When the paper is irradiated from one side, the presence of the coating can be recognized on the other side on the basis of changes in intensity that then occur. In addition, due to the transmitted light method used, it does not matter in the case of which side the cigarette paper is illuminated for carrying out the measurement, which in turn facilitates the installation of the measuring apparatus in a cigarette rod machine.

The above-mentioned coating, which is advantageously applied periodically in strips in the direction transverse to the longitudinal direction of the cigarette paper, can consist, for example, of cellulose or silicate. The coating serves, for example, as a so-called fire stop to let the cigarette go out if it is accidentally left unattended. Because less air gets through the cigarette paper at the coated areas, so that the burning process in the cigarette suffocates at the coated areas. In this way, a fire that may have been caused by leaving the bed unattended may be prevented. A particularly good contrast in the intensity of the light passing through the cigarette paper between coated and uncoated areas of the cigarette paper when carrying out the method according to the invention or in the device according to the invention results from a measurement with an incidence angle of approximately 15 ° to the surface of the cigarette paper.

It is also advantageous if the emerging light is also detected at a certain angle, preferably at an angle between 70 ° and 90 ° to the surface of the cigarette paper. This also reinforces the difference in the intensity of the light passing through the cigarette paper between coated and uncoated areas of the cigarette paper.

The contrast can be further enhanced by using polarized light, preferably linearly parallel to the surface of the cigarette paper.

Further preferred embodiments of the invention are specified in the subclaims.

An exemplary embodiment of the invention is explained below with reference to the drawing.

The drawing shows:

1 shows a cigarette rod machine in a perspective view with an embodiment of a device according to the invention; and

FIG. 2 shows a schematic illustration of the functioning of the embodiment according to FIG. 1; and

Fig. 3 is a graphical representation of a typical intensity curve detected by the photosensitive element of Fig. 2.

Fig. 1 shows a cigarette rod machine in a perspective view with an embodiment of a device according to the invention. The structure and operation of the cigarette rod machine is as follows: A pre-distributor 2 is charged with tobacco in portions from a lock 1. A removal roller 3 of the pre-distributor 2, in a controlled manner, supplements a storage container 4 with tobacco, from which a steep conveyor 5 removes tobacco and feeds a storage shaft 6 in a controlled manner. A pin roller 7 removes a uniform tobacco flow from the stowage shaft 6, which is knocked out of the pins of the pin roller 7 by a knockout roller 8 and hurled onto a scattering cloth 9 rotating at a constant speed. A tobacco fleece formed on the scattering cloth 9 is thrown into a classifying device 11, which essentially consists of an air curtain through which larger or heavier parts of tobacco pass, while all other tobacco particles are airborne into a funnel 14 formed by a pin roller 12 and a wall 13 be directed. From the pin roller 12, the tobacco is thrown into a tobacco duct 16 against a strand conveyor 17, on which the tobacco is held by means of air sucked into a vacuum chamber 18 and a tobacco rod is expanded.

A leveler 19 removes excess tobacco from the tobacco rod, which is then placed on a cigarette paper strip 21 guided in synchronism. The cigarette paper strip 21 is pulled off a bobbin 22, passed through a printing unit 23 and placed on a driven format belt 24. The format tape 24 transports the tobacco rod and the cigarette paper strip 21 through a format 26 in which the cigarette paper strip 21 is folded around the tobacco rod, so that an edge protrudes which is glued in a known manner by a glue apparatus (not shown). The adhesive seam is then closed and dried by a tandem seam plate 27.

After leaving the printing unit 23, but before being placed on the format tape 24, the cigarette paper strip 21 is passed through a device 20. The device 20 detects whether the cigarette paper strip 21 has a coating. The device 20 is described in more detail below with reference to FIGS. 2 and 3.

A cigarette rod 28 formed in this way passes through a rod density measuring device 29, which controls the equalizer 19, and is cut into double-length cigarettes 32 by a knife apparatus 31. The double-length cigarettes 32 are transferred from a transfer device 34 having controlled arms 33 to a transfer drum 36 of a filter attachment machine 37, on the cutting device of which drum 38 they are divided into single cigarettes with a circular knife. Conveyor belts 39, 41 convey excess tobacco into a container 42 arranged under the storage container 4, from which the recycled tobacco is removed again by the steep conveyor 5.

FIG. 2 shows the device 20 of FIG. 1 in a schematic illustration. The device 20 works in the transmitted light method. For this purpose, it has a laser 40, which is arranged on one side of the cigarette paper strip 21 and serves as a radiation source. However, it is also possible to use a different type of light source. The light 40a originating from the laser 40 is imaged on one side 42 of the cigarette paper strip 21 by means of focusing optics 41 which have an optical axis 40b. The light 40a is linearly polarized parallel to the surface 42 by means of a polarization filter 44 arranged on the optical axis 40b and serving as a polarization device.

The surface 42 is illuminated in a grazing incidence with an angle α = 15 ° between the surface 42 and the optical axis 40b. However, other angles 0 ° <α <75 ° are also possible. In the exemplary embodiment shown in the figure, the light 40a strikes the side 42 of the cigarette paper strip 21, which is provided with a coating 46. However, the cigarette paper strip 21 can also be guided such that the light 40a strikes the uncoated side 48. The coating 46 consists of paper strips 52 which are periodically applied to the surface 42 of the cigarette paper strip 21 and extend transversely to the longitudinal direction of the cigarette paper strip 21. However, the strips 52 can also consist of another material, for example of silicate.

The cigarette paper strip 21 moves at a speed v through the irradiation area 50 of the light 40a. In the situation shown in FIG. 2, the cigarette paper strip 21 is located with a strip 52 in the irradiation area 50.

A photosensitive element 54 serving as a detector is arranged on the side of the cigarette paper strip 21 opposite the laser 40.

The photosensitive element 54 also detects via focusing optics 56 An optical axis 57 is the intensity of the light 58 passing through the cigarette paper strip 21. The optical axis 57 of the focusing optics 56 is arranged at an angle β = 85 ° to the surface 48 of the cigarette paper strip 21. However, other angles 45 ° <β <90 ° are also possible.

Depending on whether there is a stripe 52 in the irradiation area 50 or not, the photosensitive element 54 measures a different intensity I, i.e. If the coating 46 is present, a lower intensity I is measured than if the surface 42 is uncoated. In accordance with the change in intensity, the photosensitive element 54 emits an alternating electrical signal 60 to an evaluation circuit 62. The amplitude of the electrical signal 60 corresponding to the intensity I is shown in FIG. 3 over the time t when the cigarette paper strip 21 moves through the irradiation area 50. A low amplitude corresponds to a coated area, while a high amplitude corresponds to an uncoated area.

The evaluation circuit 62 can have a memory for storing a predetermined period of the change in the intensity I and compare this stored value for checking with the currently measured value.

It is also possible for the evaluation circuit 62 to be provided with a memory for storing a table in which at least one extent of a change is associated with a specific material, for example cellulose, from which the coating 46 can be constructed. The evaluation circuit 62 can be designed to determine an average value of the intensities I over a predetermined period of time, to determine a current extent a of the change relative to the average value and to recognize from the table which coating, that is to say cellulose, for this Extent a heard. Because different coatings result in different intensity changes.

The polarization of the light 40a amplifies the change a in comparison to a transillumination of the cigarette paper strip 21 with unpolarized light.

Claims

Expectations:

1. A method for detecting a property of cigarette paper (21), comprising the steps: - The cigarette paper (21) is irradiated from one side (42) at a certain angle of incidence (α) to the cigarette paper (21) with electromagnetic radiation (40a) , the radiation (58) emerging on the other side (48) of the cigarette paper (21) is measured, - the property of the cigarette paper (21) is recorded on the basis of the measured radiation (58), characterized in that a as the angle of incidence (α) Angle between 0 ° and 75 ° is selected.

2. The method according to claim 1, wherein an angle between 5 ° and 45 ° is selected as the angle of incidence (α).

3. The method according to the preceding claim, wherein an angle between 10 ° and 20 °, preferably an angle of about 15 °, is selected as the angle of incidence (α).

4. The method according to any one of the preceding claims, wherein radiation (58) emerging at a certain exit angle (β) to the cigarette paper (21) is detected.

5. The method according to the preceding claim, wherein an angle between 45 ° and 90 ° is selected as the exit angle (β).

6. The method according to the preceding claim, wherein an angle between 70 ° and 90 ° is selected as the exit angle (β).

7. The method according to any one of the preceding claims, wherein electromagnetic radiation (40a) of a certain polarization state is used.

8. The method according to the preceding claim, wobeϊ parallel to the surface (42) of the cigarette paper (21) linearly polarized light (40a) is used.

9. The method according to any one of the preceding claims, wherein the property is an essentially periodic coating (46) of the cigarette paper (21), which detects an essentially periodic change in an intensity (I) of the measured radiation (58) while the cigarette paper (21) is moved through an irradiation area (50) of the radiation (40a).

10. The method according to the preceding claim, wherein the period of change is determined and compared for control with a predetermined period.

11. The method according to any one of the two preceding claims, wherein the extent (a) of the change relative to a mean value of the intensity (I) determined over a predetermined period of time is determined and for recognizing the material from which the coating (46) is essentially constructed , is used.

12. Device for detecting a property of cigarette paper (21), with a radiation source (40), to the cigarette paper (21) from one side at a certain angle of incidence (α) to the cigarette paper (21) with electromagnetic radiation (40a) with a detector (54) to measure radiation (58) emerging on the other side of the cigarette paper (21), with an evaluation circuit (62) to determine the property of the cigarette paper (21) based on the measured radiation (58) detect, characterized in that the incidence angle (α) is between 0 ° and 75 °.

13. The device according to the preceding claim, wherein the incidence angle (α) is between 5 ° and 45 °.

14. The device according to the preceding claim, the angle of incidence (α) is between 10 ° and 20 °, preferably around 15 °.

15. Device according to one of the two preceding claims, wherein the detector (54) is arranged to detect radiation (58) emerging from the cigarette paper (21) at a specific exit angle (β).

16. The device according to the preceding claim, wherein the exit angle (β) is between 45 ° and 90 °.

17. The device according to the preceding claim, wherein the exit angle (β) is between 70 ° and 90 °.

18. Device according to one of claims 12 to 17, with a polarization device for determining a specific polarization state of the radiation.

19. The device according to the preceding claim, wherein the polarization device (44) is arranged to polarize the radiation (40a) parallel to the surface (42) of the cigarette paper (21).

20. Device according to one of claims 12 to 19, wherein the detector (54) is designed to detect the intensity (I) of the radiation (58), and the property is a substantially periodic coating (46) of the Cigarette paper (21), which can be detected by the detector (54) via an essentially periodic change in an intensity (I) of the radiation (58) measured by the detector (54), while the cigarette paper (21) passes through an irradiation area ( 50) of the radiation source (40).

21. The device according to the preceding claim, having a memory (62) for storing a predetermined period of change, which is compared by the evaluation circuit (62) for control purposes with a current period of change determined by the evaluation circuit (62).

2. Device according to one of the two preceding claims, with a memory (62) for storing a table, in which at least one extent (a) of a change is stored assigned to a specific material from which the coating (46) can be constructed, wherein the evaluation circuit (62) is designed to determine an average value of the intensities (I) over a predetermined period of time, to determine the current extent (a) relative to the average value and to recognize from the table which coating (46) for this Extent (a) heard.