JPH0471442B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for quantitatively measuring unevenness in the flatness of a wide sheet-like material such as paper, fabric, film, or sheet. In detail, it relates to a method for quantitatively and accurately measuring the unevenness that occurs during the manufacturing and processing of sheet-like objects, such as sag (buttjii) that tends to occur in sheet-like objects and irregular sag on the side edges (loose edges). .

[Prior art]

Relatively wide sheet-like materials such as plastic film and paper cannot always maintain a constant width and constant length during manufacturing and processing. For example, in the production of synthetic resin films, sagging occurs in the center and side edges of the film due to subtle changes in stretching conditions, uneven heat treatment temperatures, non-uniform cooling conditions, and the like. The change in length in the width direction can be maintained at a predetermined width by trimming both ends, but
Local length changes in the longitudinal direction are observed as sagging.

If there is slack in the sheet material, processing operations become difficult. For example, when printing on the surface of a sheet-like object, printing misalignment may occur; for example, when coating the surface of a sheet-like object, uneven coating of the coating film or uneven coating thickness may occur. be. Typical examples include poor running of sheet materials during production and processing processes and skew in video tapes.

As a means to temporarily address such problems with the flatness of a sheet-like object and improve or restore the flatness, it is known to heat-treat the sheet-like object under tension or non-tension conditions. However, accurately measuring flatness issues is not well known. Conventional flatness restoration methods have simply relied on the experience and intuition of skilled workers and have been solved by trial and error. Therefore, the first challenge is to accurately measure the sagging of sheet-like materials and the distribution of sag occurrence, and solving these problems will result in high-quality products in the manufacturing or processing of sheet-like materials. By quantitatively measuring the distribution of sagging, we can determine the local temperature (heating/cooling conditions) and tension (defects such as tenter clips, etc.) and tension at that location of the sheet material. By knowing the state of non-uniformity (non-uniformity) and taking adjustment measures, it becomes possible to immediately apply the technology to obtain uniform, high-quality products.

[Purpose of the invention]

An object of the present invention is to provide a technique for accurately measuring the sag distribution in the width direction of a sheet-like object.

[Structure of the invention]

When a sheet-like object has slack, it cannot be quantitatively measured because of interference from surrounding parts. Therefore, the present invention slits a sheet-like material in the longitudinal direction to make a strip-shaped slit tape, and compares the predetermined length of this tape with an adjacent tape to detect local length differences. It measures and accurately determines the sagging of a sheet-like object. That is, by using the slit tape, interference from the surroundings can be eliminated. Therefore, when the length of each slit tape is measured in relation to the position in the width direction of the sheet-like article, an accurate state of the sag distribution can be obtained.

The present invention provides a method for obtaining a plurality of strip-shaped slit tapes by cutting a sheet-like material in parallel along the longitudinal direction at an intermediate portion without cutting the sheet-like material at upstream and downstream ends thereof, and for cutting the slit tape in a predetermined manner. Gripping the slit tapes at intervals, applying an external force of the same magnitude to each slit tape from a direction substantially perpendicular to the sheet surface, and measuring the amount of displacement of each slit tape due to the external force from a predetermined position. This is a method of measuring the amount of slack in a sheet-like material by comparing the values as differences in length inherent in each slit tape.

To explain the present invention, the cutting width of the slit tape when cutting a sheet-like object along the longitudinal direction is related to how precisely the slack distribution in the width direction of the sheet-like object is measured. and,
It is a good idea to select an appropriate slit width as a control indicator for production and processing. Generally, there are two selection criteria for sheet-like materials: slitting to obtain tapes with about 10 to 30 slits, or cutting to a width of about 20 to 300 mm. Of course, the width of the slit tape can be determined arbitrarily.

The slit tape is held at regular intervals by a nip roller or the like. The state before gripping must be the same state as the sheet before being slit. It is a feature of the invention that the individual lengths of the slit tape are measured while it is being held. An external force is applied from a direction substantially perpendicular to the tape at approximately the center of the gripped tape, and the amount of displacement of the tape is read at that position.

To explain this situation with reference to the drawings, FIG. 1 is a perspective view showing a state in which a sheet-like material is slit and held at predetermined intervals. The sheet material 3 whose one end is gripped by a pair of rolls, the guide roll 1 and the nip roll 2, is slit by the cutter 5 in a horizontally stretched state, and the other end is slit by the nip roll 2 in the same way as the end. It is being held in place. The slit tape is held by guide rolls and nip rolls that are pre-installed at predetermined intervals, and is vertically displaced approximately in the center by an external force (weight 4 in the figure). This vertical displacement corresponds to the length of the gripped tape, provided that the elongation of the slit tape due to external force is negligible. That is, since the tape in the sagging portion of the sheet material is longer than the tape in other portions, the amount of displacement in the vertical direction becomes large.

Figure 2 schematically shows that the displacement H in the vertical direction reflects the length in the horizontal direction, and a slight difference in length in the horizontal direction is observed as a large displacement in the vertical direction. This shows the principle behind how it can be done.

In fact, as shown in FIG. 3, if the difference in the actual length of the tape is 1 to 5 mm, it can be magnified and measured as a displacement of about 20 to 60 mm in the vertical direction. FIG. 3 also shows the ratio of the true length (talumi amount) to the displacement amount in the perpendicular direction as an amplification factor.

Figure 1 shows the case where a slitted tape is stretched horizontally, but it is possible to measure the length (sagging amount) of each tape by applying a horizontal external force to a tape stretched vertically. Needless to say. Furthermore, although a weight is used as the external force in FIG. 1, the amount of displacement under constant tension can also be measured using a device that is equipped with tension detection means and whose length can be changed. It goes without saying that such a device has a measurement principle similar to that shown in FIG. Other methods include a weight suspension method, a support method using pneumatic pressure, and an air blowing method (air micrometer, etc.)
can be exemplified.

In the present invention, the sheet-like material is slit into strips, supported at regular intervals, then nipped, and an external force is applied to measure the amount of displacement from the reference position, so the results are measured in the width direction. By arranging them side by side, the distribution of continuous sagging can be measured with high accuracy.

Furthermore, as a result of slitting into strips, the influence of adjacent interference can be completely ignored. The width when slitting into strips can be selected arbitrarily depending on the purpose and use.
When grasping the internal sag with a width of about 500 to 1000 mm, it is best to divide it into sections of about 50 to 100 mm. With the method of measuring the amount of displacement by applying an external force according to the present invention, the difference in the length of the strip can be measured in an enlarged manner, and the minute amount of sag can be amplified and read, so the measurement accuracy is greatly improved. The resolution becomes higher as the value of the external force applied during measurement is as large as possible within the elastic limit range of the object.

〔Effect of the invention〕

The sagging distribution in the width direction, which was previously impossible to grasp,
Since it can be decomposed with high accuracy, the following effects can be obtained.

It becomes possible to precisely adjust and manage the conditions of the sheet-like product manufacturing process, thereby achieving process stabilization and productivity improvement.

Quality assurance can be established according to usage and purpose.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the structure of the present invention, Fig. 2 is an explanatory view of the structure in which the weight is suspended and the amount of hanging from the reference position is expanded, and Fig. 3 shows the characteristics of the method of the present invention for each amount of sag. This is a theoretical graph. In the figure, 1: guide roll, 2: nip roll, 3: sheet-like material, 4: weight, and 5: cutter.

Claims (1)

[Claims] 1. Obtaining a plurality of strip-shaped slit tapes by cutting a sheet-like material in parallel along the longitudinal direction at an intermediate portion without cutting it at the upstream and downstream ends of the sheet-like material, and gripping the slit tapes at predetermined intervals. Apply an external force of the same magnitude to each slit tape from a direction substantially perpendicular to the sheet surface, Measure the amount of displacement of each slit tape due to the external force from a predetermined position, and calculate the value. A method of measuring the amount of slack in a sheet material by comparing the inherent length differences of each slit tape.