WO2013046401A1

WO2013046401A1 - Method for inspecting and system for inspecting cigarette filters

Info

Publication number: WO2013046401A1
Application number: PCT/JP2011/072436
Authority: WO
Inventors: 佐藤　潤
Original assignee: 日本たばこ産業株式会社
Priority date: 2011-09-29
Filing date: 2011-09-29
Publication date: 2013-04-04

Abstract

In this method for inspecting and system for inspecting cigarette filters, with the subject of inspection being hollow cigarette filters (F) having a center hole (CH), the end surface of a tobacco filter (F) is imaged by a camera (18), generating an end surface image (P), during the process of transporting the cigarette filter (F), the outer peripheral edge (OC) and inner peripheral edge (IC) of the end surface are detected by means of image processing of the end surface image (P), and it is determined whether or not the deviation in position or diameter of the center hole falls within an allowed range on the basis of the detected outer peripheral edge (OC) and inner peripheral edge (IC).

Description

Cigarette filter inspection system and inspection method thereof

The present invention relates to an inspection system suitable for inspection for a cigarette filter, particularly a center hole filter, and an inspection method thereof.

As a filter for cigarette, a center hole filter (hereinafter referred to as CH filter) is known (for example, see Patent Document 1 below). The CH filter is formed into a rod shape by thermoforming, and has a center hole penetrating the CH filter on its axis. When such a CH filter is applied to a cigarette, the CH filter is suitable for appropriately adjusting the ratio of cigarette smoke to the amount of air when cigarettes are smoked, that is, the filtration efficiency of cigarette smoke by the CH filter. .

Japanese Patent Publication No. 60-20986 (JP1985-20986 B2)

When the above-described CH filter is connected to a cigarette in the form shown in FIG. 1 or 2 of Patent Document 1 to form a filter cigarette, the center hole is at the suction end of the filter cigarette, that is, the end face of the CH filter. Exposed outside.
In this case, the center position of the center hole and the size of the center hole with respect to the axis of the CH filter have a great influence on the quality of the filter cigarette. Therefore, the center position and size of the center hole guarantees the quality of the filter cigarette. Therefore, it becomes an important inspection object.

Inspection of the center position and size of the center hole is conventionally performed by an inspector periodically removing the CH filter from the production line and visually checking the extracted CH filter. Such an off-line visual inspection of the inspector may cause a variation in inspection accuracy due to the inspection skill of the individual inspector, and a large amount of defective CH filters may be manufactured.

Under these circumstances, it is desired to develop an inspection system and an inspection method that can inspect the position and size of the center hole in the CH filter online.
Therefore, an object of the present invention is to provide an inspection system and an inspection method for the above-described CH filter.

The above object is achieved by an inspection system for a CH filter according to the present invention, which is arranged in a transfer path for transferring a hollow tobacco filter having a center hole, and images the end face of the tobacco filter to image the end face. A camera that generates an image, an image processing device that processes the image of the end face, and detects the outer and inner edges of the end face, and the center hole diameter and positional deviation are allowable based on the detected outer and inner edges. And a determination device for determining whether or not it is inside.

Specifically, the image processing device detects the outer periphery and the inner periphery of the end face as edge point distribution rings, respectively, and the determination device, based on the edge points of the distribution ring, estimates an outer circle and an inner periphery, respectively. An estimation section for calculating the estimated inner circle, a calculation section for determining the diameter of the estimated inner circle or the estimated outer circle and the center distance of the estimated inner circle, and whether or not the determined diameter or distance between the centers is within the allowable range. And a decision section to decide.

Specifically, the image processing apparatus assumes large and small search circles each having a diameter larger than the large and small prescribed diameters for the outer peripheral edge and the inner peripheral edge, and the corresponding distribution based on scanning within the range of these search circles. Detect ring edge points.
Also, the estimation section described above can use a least squares method to estimate the estimated outer circle and the estimated inner circle.
The present invention also provides an inspection method implemented by the above-described inspection system.
Furthermore, further objects and advantages of the present invention will become apparent from the following description.

According to the inspection system and inspection method of the present invention described above, the quality related to the diameter or displacement of the center hole is automatically inspected in the process of transporting the tobacco filter, so when a defective tobacco filter is detected, It is possible to eliminate defective tobacco filters from the transport path. Therefore, a defective cigarette filter is not used in the manufacture of filter cigarettes.
In addition, if the defect of the cigarette filter is fed back to the cigarette filter manufacturing machine, it greatly helps to further improve the reliability of the manufacturing machine.

It is a perspective view which shows CH filter of a test object. It is the schematic which shows the inspection system of one Example. It is a figure for demonstrating the image processing of an end surface image. It is a figure which shows the result of an image process. It is a flowchart which shows a part of test | inspection routine of one Example. It is a flowchart which shows the remainder of a test | inspection routine. It is a figure which shows the estimated outer circle and estimated inner circle of an end surface. It is a figure which shows one defect of a center hole. It is a figure which shows the other defect of a center hole. It is a figure which shows an elliptical center hole.

Referring to FIG. 1, the CH filter F as an inspection object of the present invention has a rod shape and has a center hole CH on its axis. Specifically, this type of CH filter is obtained by thermoforming a web-like filter fiber material having thermoplasticity into a rod shape.

FIG. 2 schematically shows a CH filter F manufacturing machine.
The manufacturing machine includes a thermoforming device 10, which includes a mandrel and a mold that surrounds the mandrel. In FIG. 2, the mandrel and the mold are not shown, but both the mandrel and the mold can be heated. The filter fiber material is supplied to the thermoforming apparatus 10 and is formed into a hollow continuous rod R as it passes between the mandrel and the mold. Specifically, the mandrel and the forming die thermoform the inner peripheral surface and the outer peripheral surface of the continuous rod R, respectively.

The formed continuous rod R is sent from the thermoforming device 10 toward the cutting device 12, which cuts the continuous rod R into individual CH filters F, while passing these CH filters F along the delivery line DL. Transmit intermittently.
The delivered CH filter F is received by the transfer path TL, and then transferred to the subsequent boxing machine or filter cigarette manufacturing machine on the transfer path TL. Specifically, the transfer path TL includes a catcher drum 14 at the start thereof, and the catcher drum 14 is disposed downstream of the cutting device 12. The catcher drum 14 has an axis parallel to the delivery line DL, and can rotate around this axis.

Specifically, the catcher drum 14 includes a number of receiving seats 16, and these receiving seats 16 are arranged on the outer peripheral surface of the catcher drum 14 at equal intervals. While the catcher drum 14 is rotating, each receiving seat 16 sequentially passes through the delivery line DL described above.
Specifically, each receiving seat 16 receives one CH filter F sent from the cutting device 12 when passing through the sending line DL, and holds the received CH filter F by suction in the circumferential direction of the catcher drum 14. Transport to. That is, the catcher drum 14 converts the transfer direction of the CH filter F into a direction orthogonal to the axial direction of the CH filter F.

In the transfer path TL described above, a part of the inspection system for the CH filter F, that is, the inspection camera 18 is arranged. Specifically, the inspection camera (CCD camera) 18 is positioned in the vicinity of the catcher drum 14 and sequentially photographs the end face of the CH filter F transferred along the outer peripheral surface of the catcher drum 14.
Further, a ring light 20 as a light source is disposed between the inspection camera 18 and the catch drum 14, and the ring light 20 uniformly illuminates the end face of the CH filter F passing through the inspection camera 18.

Further, a trigger sensor 22 is disposed upstream of the inspection camera 18 when viewed in the transfer direction of the CH filter F on the catcher drum 14. The trigger sensor 22 optically detects passage of the CH filter F, and transmits a trigger signal to the inspection camera 18 at a timing when the detected CH filter F passes the inspection camera 18. Therefore, the inspection camera 18 can capture the end face of the CH filter F passing through the inspection camera 18 by performing an imaging operation at the timing when the trigger signal is received, and transmits the captured end face image as an electrical signal. To do.

On the other hand, the inspection camera 18 is electrically connected to the image processing device 24, and the image processing device 24 receives an electrical signal transmitted from the inspection camera 18, that is, an end face image, and outputs the end face image to the end face image. Predetermined image processing is performed.
Specifically, the image processing device 24 has software for performing edge detection processing on the end face image, and extracts the outer peripheral edge of the CH filter F and the inner peripheral edge of the center hole CH. The extraction here will be specifically described with reference to FIGS.

When it is assumed that the image processing device 24 includes the display screen 26, FIG. 3 shows an end face image P of the CH filter F arranged at the center of the display screen 26. Here, in order to clearly show the end face image P, hatching is added to the end face image P, while distortions of the outer peripheral edge OE and the inner peripheral edge IE in the end face image P are exaggerated.

As apparent from FIG. 3, search circles C _I and C _O inside and outside are drawn on the display screen 26, and these search circles C _I and C _O both have a diameter centered on the reference position O at the center of the display 26. Have. Specifically, although the diameter of the inner search circle C _I is sufficiently larger than the predetermined diameter of the inner peripheral edge IE, smaller than the specified diameter of the outer peripheral edge OE, contrast, the diameter of the outer search circle C _O peripheral edge OE Is sufficiently larger than the prescribed outer diameter.

Then, the display screen 26, along a single scan line SL around the reference position of O, scanned from the inner position than the defined diameter of the inner peripheral edge IE to search circle C _O through the search circle C _I, the scanning The positions of the inner peripheral edge IE and the outer peripheral edge OE existing on the line SL are detected. The position detection here is performed based on the difference between the pixel density of the background on the display screen 26 and the pixel density of the end face image P.

Thereafter, the position detection of the inner peripheral edge IE and the outer peripheral edge OE described above is repeated over the entire circumference of the end face image P while the scanning line SL is shifted by a predetermined angle in the circumferential direction of the end face image P.
As a result of the position detection described above, the inner peripheral edge IE or the outer peripheral edge OE is represented by a distribution ring of edge points EP as shown in FIG.
The search circles C _I and C _O described above minimize the scanning range of the inner peripheral edge IE and the outer peripheral edge OE, and greatly contribute to efficient detection of the edge point EP. .

As shown in FIG. 2, the above-described image processing device 24 is electrically connected to the determination device 28, and transfers the inner and outer distribution rings representing the inner peripheral edge IE and the outer peripheral edge OE to the determination device 28.
The determination device 28 has software for determining the quality of the center hole CH based on the transferred distribution ring, and the determination procedure here becomes clear from the inspection routines shown in FIGS.

The inspection routine will be described in detail below.
Steps S1 and S2 shown in FIG. 5 are included in the software of the image processing device 24 described above, and the software of the determination device 28 includes steps after step S3.
First, in step S3, the center hole CH is shown based on the least square method from each edge point EP (see FIG. 4) representing the positions of the inner peripheral edge IE and the outer peripheral edge OE as viewed in XY coordinates centered on the reference position O. An estimated inner circle and an estimated outer circle indicating the outer periphery of the CH filter F are calculated.

Next, the radius and center of each of the estimated inner circle and the estimated outer circle, and the center distance between the center of the estimated inner circle and the center of the estimated outer circle are calculated (step S4).
Referring to FIG. 7, the estimated inner circle and the estimated outer circle are denoted by reference symbols IC and OC, respectively, and the radius and center of the estimated inner circle and the estimated outer edge are denoted by R _I and R _O and the centers O _I and O _O. Has been. In FIG. 7, reference symbol ΔD indicates the center-to-center distance.

Next, in the case of the present embodiment, whether or not the diameter of the estimated outer circle OC obtained from the radius R _O is within an allowable range (step S5), and the diameter of the estimated inner circle IC calculated from the radius R _I is allowed. It is sequentially determined whether or not it is within the range (step S6) and whether or not the center-to-center distance ΔD is within the allowable range (step S7).
When the determination result of any of steps S5 to S7 is false (No), step S8 shown in FIG. 6 is performed, and in this step S8, a failure indicating that the CH filter F to be inspected is defective. A signal is output, and the failure signal here includes the degree of failure and the location of the failure.

Specifically, when the determination result in step S5 is false, it indicates that the diameter of the CH filter F is out of the standard. When the determination result in step S6 is false, the diameter of the center hole CH is out of the standard. Indicates that it is off. If the determination result in step S7 is false, it indicates that the center of the center hole CH is greatly out of the axis of the CH filter F.
For example, the failure signal can be used to adjust the outer diameter of the CH filter F to be manufactured and the diameter of the center hole CH with respect to the manufacture of the CH filter F by the thermoforming apparatus 10 described above, while the transfer path TL. Therefore, it can be used to eliminate defective CH filter F.

Therefore, as described above, the inspection regarding the outer diameter and inner diameter of the CH filter F and the positional deviation of the center hole CH is performed online, and the defective CH filter F can be excluded from the transfer path TL. Therefore, the defective CH filter F is not supplied to the aforementioned boxing machine or filter cigarette manufacturing machine. As a result, the manufacture of a filter cigarette including a defective CH filter F is reliably avoided.

On the other hand, if all the determination results in steps S5 to S7 are true (Yes), the steps after step S9 shown in FIG. 6 are performed.
In step S9, the model wheel of the center hole CH, that is, the reference model line is read. In the present embodiment, since the center hole CH is a circle, the reference model line is a reference circle. Based on this reference circle, the smoothness of the inner peripheral surface of the center hole CH is detected (step
S10).

Specifically, with the center of the reference circle BC and the center of the distribution ring DR of the edge point EP indicating the center hole CH matched to each other, as shown in FIG. Ring DR is superimposed. In FIG. 8, a region SA in which the reference circle BC and the distribution ring DR are separated from each other is shown as a line, and this region SA indicates a recess in the inner peripheral surface of the center hole CH.

Then, regarding a line segment passing through the center of the reference circle BC and one edge point EP on the distribution ring DR and intersecting the reference circle BC, the difference between the reference circle BC and the edge point EP on this line segment A distance ΔL is calculated. Such a difference distance ΔL is calculated for all edge points EP.
A difference distance ΔL _O outside the allowable range is extracted from the obtained difference distance ΔL, and this difference distance ΔL _O indicates the degree of defects related to smoothness. Therefore, the maximum value of the difference distance ΔL _O indicates, for example, the maximum defect level of the area SA.

Thereafter, the number N of edge points EP having the difference distance ΔL _O is counted, where N indicates, for example, the width of the area SA. Next, the non-smooth amount DA (= T × N) obtained by multiplying the sum T of the difference distance ΔL _{O by} the number N is obtained (step S10).
Thereafter, in the next step S11, it is determined whether or not the non-smooth amount DA is within the allowable range. If the determination result here is false, step S8 described above is performed.

Here, the area SA shown in FIG. 8 is a bump-like defect protruding from the inner peripheral surface of the center hole CH, but is recessed from the inner peripheral surface of the center hole CH as shown in FIG. 9A. A defect in the area SA or a defect in the area SA where the filter fibers forming the CH filter F are fluffed from the inner peripheral surface of the center hole CH as shown in FIG. Needless to say, it is included.

On the other hand, when the determination result in step S11 is true, the maximum diameter and the minimum diameter of the distribution ring DR of the edge point EP are calculated (step S12). Specifically, with respect to a plurality of pairs of edge points EP spaced apart in the diameter direction of the search circle C ₁ across the center of the search circle C ₁ , that is, the reference position O, the separation distance between the paired edge points EP. Are respectively calculated. As shown in FIG. 10, the maximum and minimum separation distances among the separation distances are determined as the maximum diameter LD and the minimum diameter SD.

Next, a diameter difference ΔE (= LD−SD) between the maximum diameter LD and the minimum diameter SD is calculated (step S13), and it is determined whether or not the diameter difference ΔE is within an allowable range. (Step S14).
The situation in which the determination result in step S14 is false indicates that the distribution ring DR, that is, the center hole CH is not a circle but an ellipse. In this case, the above-described step S8 is performed from step S14, and a failure signal is output.

On the other hand, when the determination result of step S14 is true, the steps after step S1 are repeatedly performed to check the next CH filter F.
In the steps after Step S9 described above, an appearance defect of the center hole CH is inspected for non-smoothness and non-roundness of the inner peripheral surface of the center hole CH, and the CH filter F having the appearance defect is also removed from the transfer path TL. Since it can be eliminated, the production of defective filter cigarettes due to appearance defects is also reliably avoided.

Further, as is apparent from the inspection routines of FIGS. 5 and 6, when the determinations in steps S5, S6, S7, S11, and S14 are sequentially performed and the determination result is false in any step, the inspection routine is performed. After outputting the failure signal in step S8, the inspection of the CH filter F that is the inspection object is terminated, so that the inspection routine is not performed wastefully. In addition, since the failure signal can indicate a failure location of the CH filter F, it is useful for manufacturing management of the CH filter F.

The present invention is not limited to the inspection system and inspection method of the above-described embodiment, and various modifications can be made without departing from the technical idea of the present invention. For example, the inspection system and the inspection method of the present invention may inspect whether the diameter or the positional deviation of the center hole is within an allowable range.

10 thermoforming apparatus 12 cutting device 14 catcher drum 18 camera 20 ring light 24 image processing apparatus 28 determines device F CH filter O reference position O _I, O _O center R _I, R _O radius P end face image BC reference circle C _I, _{C o} Search circle CH Center hole DL Transmission line DR Distribution ring EP Edge point IC Estimated inner circle IE Inner edge OC Estimated outer circle OE Outer edge SL Scan line TL Transfer path ΔD Center distance ΔL Difference distance

Claims

A camera arranged in a transfer path for transferring a hollow cigarette filter having a center hole, and imaging an end face of the cigarette filter to generate an end face image;
An image processing device for processing an image of the end face and detecting an outer peripheral edge and an inner peripheral edge of the end face;
An inspection system for a cigarette filter, comprising: a determination device that determines whether a diameter or a positional deviation of the center hole is within an allowable range based on the detected outer periphery and inner periphery.
The image processing device detects the outer peripheral edge and the inner peripheral edge of the end face as edge point distribution rings,
The determination device includes:
An estimation section for obtaining an estimated outer circle and an estimated inner circle representing the outer periphery and the inner periphery, respectively, based on the edge points of the distribution ring;
A calculation section for obtaining a diameter of the estimated inner circle or a distance between centers of the estimated outer circle and the estimated inner circle;
A determination section for determining whether the determined diameter or the center-to-center distance is within an acceptable range;
An inspection system for a tobacco filter according to claim 1.
The image processing apparatus assumes large and small search circles each having a diameter larger than the large and small prescribed diameters for the outer peripheral edge and the inner peripheral edge, and a corresponding distribution based on scanning within the range of the search circles. 3. The inspection system for tobacco filter according to claim 2, wherein an edge point of the ring is detected.
3. The inspection system for tobacco filter according to claim 2, wherein the estimation section uses a least square method to estimate the estimated outer circle and the estimated inner circle.
3. The inspection system for a tobacco filter according to claim 2, wherein the determination section outputs a failure signal when the obtained diameter or the center-to-center distance is out of an allowable range.
The inspection system for a tobacco filter according to claim 2, wherein the transfer path is connected to a delivery line extending from the tobacco filter manufacturing apparatus.
The transfer path includes a catcher drum that receives the cigarette filter from the production line at its start end and transfers the received cigarette filter;
The inspection system for a tobacco filter according to claim 6, wherein the camera is disposed in the vicinity of the catch drum.
In the process of transferring a hollow cigarette filter having a center hole along the transfer path, an end face image is generated by imaging the end face of the cigarette filter with a camera,
Image processing the end face image to detect an outer edge and an inner edge of the end face;
An inspection method for a cigarette filter, characterized in that it is determined whether a diameter or a positional deviation of the center hole is within an allowable range based on the detected outer peripheral edge and inner peripheral edge.
The image processing detects the outer periphery and the inner periphery of the end face as edge point distribution rings,
The determination of the diameter or displacement is as follows:
An estimation process for obtaining an estimated outer circle and an estimated inner circle representing the outer periphery and the inner periphery, respectively, based on the edge points of the distribution ring;
A calculation process for obtaining a diameter of the estimated inner circle or a distance between centers of the estimated outer circle and the estimated inner circle;
Determining whether the obtained diameter or the center-to-center distance is within an acceptable range;
9. The inspection method for a tobacco filter according to claim 8, wherein
The image processing assumes large and small search circles each having a larger diameter than the large and small prescribed diameters for the outer periphery and the inner periphery, and based on scanning within these search circles, the corresponding distribution ring 10. The inspection method for a tobacco filter according to claim 9, wherein an edge point of the tobacco filter is detected.
10. The inspection method for a tobacco filter according to claim 9, wherein the estimation process uses a least square method to estimate the estimated outer circle and the estimated inner circle.
10. The inspection method for a tobacco filter according to claim 9, wherein the determination process outputs a failure signal when any of the diameter and the distance between the centers is out of an allowable range.