JP3806563B2 - Heat seal position detection device for plastic film - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a heat seal position detecting device for a plastic film.
[0002]
[Prior art and its problems]
For example, in a bag making machine that manufactures plastic bags, a micro uneven surface of a pattern such as a mesh is formed on the heat seal portion of the plastic film, the plastic film is intermittently fed in the length direction, is run, and the heat seal portion or In the vicinity, the plastic film is often cut by a cutter. In this case, it is required to accurately cut the plastic film at or near the heat seal portion, and in order to achieve this, when the plastic film is traveling in the length direction, the heat seal position of the plastic film in advance is required. Need to be detected. Therefore, before filing this application, the applicant developed and proposed a new type of heat seal position detection device. This is what is described in JP-A-11-190608.
[0003]
In the apparatus disclosed in the publication, a light source and an optical sensor face a plastic film, and light is emitted from the light source. The optical sensor receives reflected light or transmitted light from the plastic film. Therefore, when the heat seal part reaches the installation position of the light source and the optical sensor, the reflected light or transmitted light is redirected by the minute uneven surface of the heat seal part, and the amount of light received by the optical sensor changes. When a difference in the wave shape occurs in the amount of light received by the optical sensor in the width direction of the plastic film, the minute uneven surface of the heat seal portion is read by the waveform. In this case, 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. The reason is considered to be the relationship between the minute uneven surface of the heat seal portion and the amount of light received by the optical sensor. As the plastic film travels, it is clear that the reflected or transmitted light is redirected by the micro uneven surface of the heat seal portion, but the direction of the deflection is extremely complicated. Therefore, even if the reflected light or transmitted light changes, the difference in the wave shape does not necessarily occur in the amount of light received by the optical sensor, and the corrugated surface of the heat seal portion cannot be read by the waveform, and the plastic film It is considered that the heat seal position of this cannot be detected.
[0004]
OBJECT OF THE INVENTION
Therefore, the present invention has been made for the purpose of reliably detecting the heat seal position of the plastic film.
[0005]
[Structure of the invention]
According to the present invention, in an apparatus for detecting a heat seal position of a plastic film traveling in the length direction, the light source and the optical sensor are opposed to the plastic film. A shielding plate is disposed between the optical sensor and the plastic film. Furthermore, a plurality of holes or slits are formed in the shielding plate. Therefore, light is emitted from the light source, the reflected or transmitted light of the plastic film is passed through the hole or slit of the shielding plate, guided to the optical sensor, and the reflected or transmitted light that has passed through the hole or slit is image-recognized by the optical sensor. By the change of the image, the micro uneven surface of the heat seal portion can be read and the heat seal position of the plastic film can be detected.
[0006]
Multiple light sources are spaced from each other, thereby producing multiple reflected or transmitted light, 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. It is preferable to be allowed to do so.
[0007]
[Explanation of Examples]
Examples of the present invention will be described below.
[0008]
In FIG. 1, this is for detecting the heat seal position of the plastic film 1, and is an accessory device of the bag making machine. The plastic film 1 is superimposed on a plurality of layers and intermittently fed in the length direction X. Running is the same as that of the above publication. Each time the plastic film 1 is intermittently fed, the plastic film 1 is heat-sealed in the width direction, and then, every intermittent feed, the plastic film 1 is cut by a cutter at or near the heat-sealed portion 2, thereby a plastic bag. Is manufactured in the same manner as that of the publication. The Teflon sheet or minute uneven surface of the seal bar or cooling bar is pressed against the heat seal portion 2 to form a fine uneven surface with a pattern such as a mesh on the heat seal portion 2 as in the same publication.
[0009]
In this apparatus, on the upper side of the plastic film 1, the light source 3 and the optical sensor 4 are opposed to the plastic film 1, and the shielding plate 5 is disposed between the optical sensor 4 and the plastic film 1. The position is a position downstream of the seal bar and the cooling bar, and is a position upstream of the cutter. The optical sensor 4 is 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, formed at intervals in the length direction X and the width direction of the plastic film 1, and arranged in a square shape. The pitch P1 is 5 to 10 mm. Furthermore, the hole 6 consists of a round hole, and the diameter is about 0.5 mm. Therefore, the light from the light source 3 is irradiated, the reflected light of the plastic film 1 is passed through the hole 6 of the shielding plate 5 and guided to the optical sensor 4, and the hole 6 of the shielding plate 5 can be recognized by the optical sensor 4.
[0011]
Further, in this embodiment, a plurality of light sources 3 are arranged at intervals from each other, thereby generating a plurality of reflected lights, each reflected light having a different angle, and this being formed in the hole 6 of the shielding plate 5. Through, it can be guided to the optical sensor 4. For example, two light sources 3 are arranged at intervals in the length direction X of the plastic film 1, and each reflected light has different angles α and β, passes through the holes 6 of the shielding plate 5, and passes through the optical sensor 4. Led. Accordingly, the four holes 6 can be image-recognized by one reflected light, and the four holes 6 can be image-recognized by the other reflected light. As shown in FIG. 3, a total of eight holes 6 are image-recognized. Can do.
[0012]
When the plastic film 1 travels in the length direction and the heat seal portion 2 reaches the installation position of the light source 3 and the optical sensor 4, the reflected light is redirected by the minute uneven surface of the heat seal portion 2. 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 changed as shown in FIG. As a result, the minute uneven surface of the heat seal portion 2 can be read, and the heat seal position of the plastic film 1 can be reliably detected.
[0013]
5 and 6 show another embodiment. In this embodiment, nine holes 6 are provided in the shielding plate 5 and formed at intervals in the length direction X and the width direction of the plastic film 1 and arranged in three rows. The pitch P1 is constant and is 5 to 10 mm. Furthermore, around the hole 6 of the shielding plate 5, 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.
[0014]
P2 = 3 × P1
[0015]
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 these are passed through the holes 6 of the shielding plate 5, and passed to the optical sensor 4. Can lead. Therefore, in each reflected light, nine holes 6 can be image-recognized, and a total of 36 holes 6 can be image-recognized.
[0016]
In short, the number of holes 6 for image recognition can be doubled by the number of light sources 3. And the micro unevenness | corrugation surface of the heat seal part 2 can be read by the image change, and the heat seal position of the plastic film 1 can be detected reliably.
[0017]
Further, in the embodiment of 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, but the light is substantially perpendicular to the plastic film 1. For this reason, even if the height of the plastic film 1 varies to some extent, the image of the hole 6 is not disturbed by this, which is preferable.
[0018]
Instead of the plurality of holes 6, a plurality of slits are formed in the shielding plate 5, the reflected light of the plastic film 1 is passed through it, guided to the optical sensor 4, and the optical sensor 4 recognizes the image of the slits of the shielding plate 5. Also good. Thereby, the minute uneven surface of the heat seal portion 2 can be read, and the heat seal position of the plastic film 1 can be detected.
[0019]
The light source 3 and the optical sensor 4 may be opposed to the plastic film 1 and the shielding plate 5 may be disposed between the optical sensor 4 and the plastic film 1 on the lower side instead of the upper side of the plastic film 1. Then, when the reflected light of the plastic film 1 passes through the hole 6 or slit of the shielding plate 5 and is guided to the optical sensor 4, the minute uneven surface of the heat seal portion 2 is thereby read, and the heat seal position of the plastic film 1 is read. Can be detected.
[0020]
As shown in FIG. 7, the light source 3 is opposed to the plastic film 1 on one side of 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 optical sensor. 4 and the plastic film 1 may be disposed. Then, when light is emitted from the light source 3 and the light transmitted through the plastic film 1 is passed through the hole 6 or slit of the shielding plate 5 and guided to the optical sensor 4, the optical sensor 4 recognizes the image of the hole 6 or slit of the shielding plate 5. Then, by the image change, the minute uneven surface of the heat seal portion 2 can be read and the heat seal position of the plastic film 1 can be detected.
[0021]
【The invention's effect】
As described above, according to the present invention, light is emitted from the light source 3, and reflected light or transmitted light of the plastic film 1 passes through the hole 6 or slit of the shielding plate 5 and is guided to the optical sensor 4. 4, the image of the hole 6 or the slit of the shielding plate 5 is recognized, and the minute uneven surface of the heat seal portion 2 is read by the image change. Therefore, the heat seal 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.
FIG. 3 is an explanatory diagram of an image of the optical sensor in FIG. 1;
4 is an explanatory view showing a state in which the image of the hole in FIG. 3 is disturbed. FIG.
FIG. 5 is a side view showing another embodiment.
6 is a bottom view of the shielding plate of FIG. 5. FIG.
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 Shielding plate 6 Hole

Claims (2)

A device for detecting the heat seal position of a plastic film that has a micro uneven surface of a pattern such as a mesh and that runs in the length direction,
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;
It consists of a plurality of holes or slits formed in the shielding plate,
Light is emitted from the light source, the reflected light or transmitted light of the plastic film is passed through the hole or slit of the shielding plate, guided to the optical sensor, and the reflected light or transmitted light passed through the hole or slit by the optical sensor. An apparatus for detecting a heat seal position of a plastic film, wherein the heat seal position of the plastic film is detected by recognizing the image and reading the micro uneven surface of the heat seal portion according to the image change. A plurality of the light sources are spaced apart from each other, thereby generating a plurality of reflected light or transmitted light, each reflected light or transmitted light having a different angle, passing through the hole or slit of the shielding plate, apparatus according to claim 1, characterized in that the so that led to the optical sensor.

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