JP2001188006A - Heat seal position detecting device for plastic film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely detect the heat seal position of a plastic film 1. SOLUTION: The light is emitted from a light source 3, and the light reflected on a plastic film or transmission light is allowed to pass a hole 6 of a shield plate 5 or a slit, which is led to an optical sensor 4. The optical sensor recognizes the hole of shield plate or slit by image and reads a minute rough surface of a heat seal part 2 based on the image change, thus detecting a heat seal of the plastic film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting the position of heat sealing a plastic film.

[0002]

2. Description of the Related Art For example, in a bag making machine for manufacturing a plastic bag, a fine irregular surface of a pattern such as a mesh is formed on a heat-sealed portion of the plastic film, and the plastic film is intermittently fed in a length direction. In many cases, the plastic film is cut by a cutter at or near the heat-sealed portion. In this case, it is required to cut the plastic film accurately at or near the heat-sealed portion. To achieve this, when the plastic film is running in the longitudinal direction, the heat-sealing position of the plastic film is determined in advance. Need to be detected. Therefore, before the filing of the present application, the applicant has developed and proposed a new type of heat seal position detecting device. JP 1
That is described in JP-A-1-190808.

In the device disclosed in the publication, a light source and an optical sensor face a plastic film, light is emitted from the light source, and the optical sensor receives reflected light or transmitted light from the plastic film. Therefore, when the heat-sealed portion reaches the installation position of the light source and the optical sensor, the reflected light or transmitted light is diverted by the minute uneven surface of the heat-sealed portion, and the amount of light received by the optical sensor changes. And
When a wave-shaped difference occurs in the amount of light received by the optical sensor in the width direction of the plastic film, the minute irregular surface of the heat seal portion is read by the waveform. Thus, the heat seal position of the plastic film is detected. However, in the case of the apparatus disclosed in the publication, the heat seal position of the plastic film may not actually be detected, and there is a problem in its reliability. It is considered that the reason is that there is a relationship between the minute uneven surface of the heat seal portion and the amount of light received by the optical sensor. It is clear that the reflected light or transmitted light is diverted by the minute uneven surface of the heat seal portion as the plastic film runs, but the diverted state is extremely complicated. Therefore, even if the reflected light or the transmitted light changes direction, the amount of light received by the optical sensor does not always cause a difference in the wave shape, and the waveform cannot read the minute uneven surface of the heat-sealed portion. It is considered that the heat seal position cannot be detected.

[0004]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to reliably detect a heat sealing position of a plastic film.

[0005]

According to the present invention, there is provided an apparatus for detecting a heat seal position of a plastic film running in a longitudinal direction, having a heat seal portion having a fine irregular surface of a pattern such as a mesh, and a light source and an optical sensor. Faces the plastic film, and the shielding plate is disposed between the optical sensor and the plastic film. Further, a plurality of holes or slits are formed in the shielding plate. Therefore, light is emitted from the light source, reflected light or transmitted light of the plastic film is passed through the holes or slits of the shielding plate, guided to the optical sensor, and the optical sensor recognizes the image of the holes or slits of the shielding plate, and the image changes. By reading the minute uneven surface of the heat seal portion, the heat seal position of the plastic film can be detected.

[0006] A plurality of light sources are spaced apart from each other,
This preferably produces a plurality of reflected or transmitted lights, with each reflected or transmitted light having a different angle, passing through a hole or slit in the shielding plate and guided to the optical sensor.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.

In FIG. 1, this is for detecting the heat sealing position of the plastic film 1 and is an accessory device of a bag making machine. Feeding and running are the same as in the above publication. Each time the plastic film 1 is intermittently fed, the plastic film 1 is heat-sealed in its width direction. Then, each time the plastic film 1 is intermittently fed, the plastic film 1 is cut at or near the heat-sealed portion 2 by a cutter. Is produced in the same manner as in the publication. The Teflon sheet of the seal bar or the cooling bar or the micro-textured surface is pressed against the heat-sealed portion 2 to form a micro-textured surface of a pattern such as a mesh on the heat-sealed portion 2 as in the publication.

In this device, the light source 3 and the optical sensor 4 face the plastic film 1 above the plastic film 1, and the shielding plate 5 is disposed between the optical sensor 4 and the plastic film 1. Its location is downstream of the seal bar and cooling bar,
This is the position upstream of the cutter. The optical sensor 4 comprises a CCD camera.

[0010] Further, as shown in FIG. 2, a plurality of holes 6 are formed in the shielding plate 5. For example, four holes 6 are provided in the shielding plate 5, are formed at intervals in the length direction X and the width direction of the plastic film 1, and are arranged in a square shape. The pitch P1 is 5 to 10 mm.
Further, the hole 6 is composed of a round hole, the diameter of which is approximately 0.5.
mm. Therefore, light is emitted from the light source 3 and the reflected light of the plastic film 1 passes through the hole 6 of the shielding plate 5,
The light is guided to the optical sensor 4, and the image of the hole 6 of the shielding plate 5 can be recognized by the optical sensor 4.

Further, in this embodiment, a plurality of light sources 3 are arranged at intervals from each other, thereby generating a plurality of reflected lights, and giving each reflected light a different angle.
This can be guided to the optical sensor 4 through the hole 6 of the shielding plate 5. For example, two light sources 3 are arranged at intervals in the longitudinal direction X of the plastic film 1, and each reflected light has a different angle α, β, passes through the hole 6 of the shielding plate 5, Be guided. Therefore, four holes 6 can be image-recognized by one reflected light, and four holes 6 can be image-recognized by the other reflected light. As shown in FIG. Can be.

When the plastic film 1 travels in the longitudinal direction and the heat seal portion 2 reaches the position where the light source 3 and the optical sensor 4 are installed, the reflected light is diverted by the minute uneven surface of the heat seal portion 2. Is done. Therefore, when the reflected light of the heat seal portion 2 passes through the hole 6 of the shielding plate 5 and is guided to the optical sensor 4, the image of the hole 6 is greatly disturbed and changes as shown in FIG. As a result, the minute uneven surface of the heat seal portion 2 is read, and the heat seal position of the plastic film 1 can be reliably detected.

FIGS. 5 and 6 show another embodiment. In this embodiment, nine holes 6 are provided in the shielding plate 5, are formed at intervals in the length direction X and the width direction of the plastic film 1, and are arranged in three rows. The pitch P1
Is constant and is 5 to 10 mm. Further, the shielding plate 5
Around the hole 6, four light sources 3 are provided at intervals in the length direction X and the width direction of the plastic film 1 and are arranged in a square shape. The pitch P2 is three times as large as the pitch P1 of the holes 6.

P2 = 3 × P1

In this case, when light is emitted from each light source 3, the four reflected lights have different angles in the length direction X and the width direction of the plastic film 1 and pass through the holes 6 of the shielding plate 5, and It can be led to the sensor 4. Therefore, in each reflected light, nine holes 6 can be image-recognized, and a total of 36 holes 6 can be image-recognized.

In short, the number of holes 6 for image recognition can be doubled by the number of light sources 3. Then, the minute uneven surface of the heat seal portion 2 can be read by the image change, and the plastic film 1
Can be reliably detected.

Further, in the embodiment shown in FIG. 5, the reflected light of the plastic film 1 passes through the hole 6 of the shielding plate 5 and is guided to the optical sensor 4, and the light is substantially perpendicular to the plastic film 1. In this connection, even if the height of the plastic film 1 fluctuates to some extent, the image of the hole 6 is not disturbed by the fluctuation, which is preferable.

Instead of the plurality of holes 6, a plurality of slits are formed in the shielding plate 5, and the reflected light of the plastic film 1 passes through the shielding film 5 and is guided to the optical sensor 4, and the slits of the shielding plate 5 are image-recognized by the optical sensor 4. You may do so.
Thereby, the minute uneven surface of the heat seal portion 2 is read, and the heat seal position of the plastic film 1 can be detected.

Instead of being above the plastic film 1,
On the lower side, the light source 3 and the optical sensor 4 may face the plastic film 1, and the shielding plate 5 may be arranged between the optical sensor 4 and the plastic film 1. When the reflected light of the plastic film 1 passes through the hole 6 or the slit of the shielding plate 5 and is guided to the optical sensor 4, the minute uneven surface of the heat sealing portion 2 is read, and the heat sealing position of the plastic film 1 is read. Can be detected.

As shown in FIG. 7, on one side of the plastic film 1, the light source 3 is connected to the plastic film 1.
The optical sensor 4 is opposed to the plastic film 1 on the other side of the plastic film 1, and the shielding plate 5 is attached to the optical sensor 4 and the plastic film 1.
It may be arranged between them. Then, light is emitted from the light source 3,
When the transmitted light of the plastic film 1 passes through the hole 6 or the slit of the shielding plate 5 and is guided to the optical sensor 4, the optical sensor 4 recognizes the image of the hole 6 or the slit of the shielding plate 5, and a change in the image causes the heat sealing portion 2. , The heat sealing position of the plastic film 1 can be detected.

[0021]

As described above, according to the present invention, light is emitted from the light source 3 and the plastic film 1 is irradiated with light.
The reflected light or transmitted light passes through the hole 6 or the slit of the shielding plate 5 and is guided to the optical sensor 4. The optical sensor 4 recognizes the image of the hole 6 or the slit of the shielding plate 5. Is read. Therefore, the heat sealing position of the plastic film 1 can be reliably detected, and the intended purpose can be achieved.

[Brief description of the drawings]

FIG. 1 is a side view showing an embodiment of the present invention.

FIG. 2 is a bottom view of the shielding plate of FIG. 1;

FIG. 3 is an explanatory diagram of an image of the optical sensor of FIG. 1;

FIG. 4 is an explanatory diagram showing a state in which the image of the hole in FIG. 3 is disturbed.

FIG. 5 is a side view showing another embodiment.

FIG. 6 is a bottom view of the shielding plate of FIG. 5;

FIG. 7 is a side view showing another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plastic film 2 Heat seal part 3 Light source 4 Optical sensor 5 Shield plate 6 hole

Claims (2)

[Claims] 1. A device for detecting a heat sealing position of a plastic film running in a longitudinal direction, the device having a heat sealing portion having a fine uneven surface of a pattern such as a mesh, and a light source facing the plastic film. An optical sensor facing the plastic film, a shielding plate disposed between the optical sensor and the plastic film, and a plurality of holes or slits formed in the shielding plate, and irradiates light from the light source. Passing the reflected light or transmitted light of the plastic film through the holes or slits of the shielding plate, guiding the light to the optical sensor, recognizing an image of the holes or slits of the shielding plate by the optical sensor, and changing the image by the heat seal. Read the micro uneven surface of the part, and check the heat seal position of the plastic film A plastic film heat seal position detecting device, wherein the position is detected. 2. A plurality of said light sources being spaced apart from each other, thereby producing a plurality of said reflected or transmitted light, each of said reflected or transmitted light having a different angle, and a hole in said shielding plate. The apparatus according to claim 1, wherein the optical sensor is guided to the optical sensor through a slit.