JPH05162901A - Joining method for tube film - Google Patents

Abstract

PURPOSE:To obviate the need of pressing up of a plate cylinder and to minimize the production of a mis-printed paper sheet in the case of joining the starting end portion of a following tube film to the terminal end portion of a preceding tube film supplied to a flexographic press. CONSTITUTION:A designated portion of the starting end of a following tube film 1 fed from a roll body 2 is sealed by a heat seal part 11, and the forward end side from the heat seal part 11 is excised in one sheet of a film part 1a. One sheet of a film part 1a and the terminal end portion of a preceding tube film 1 are joined to each other through a thin splicing joining film 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of joining a trailing end portion of a preceding tube film and a trailing end portion of a following tube film when switching a material, for example, when printing on a tube film using a flexographic printing machine. ..

[0002]

2. Description of the Related Art In the production of packaging bags for disposable diapers, polyethylene as a material is molded into a tube,
In some cases, a method is used in which the tube film thus produced is supplied to a flexographic printing machine to print a pattern on the front and back surfaces and then molded into a bag. In that case, a drum type (single cylinder type) is usually used as the flexographic printing machine. This drum-type flexographic printing machine is configured by arranging, for example, four printing units around a common impression cylinder, and the tube film makes one round around the impression cylinder. It is configured such that each color is printed on one side. According to such a flexographic printing machine, different patterns can be formed on the right and left portions of the plate cylinder by utilizing the wide plate width of the plate cylinder that comes into contact with the impression cylinder. By passing the left side part and the right side part respectively, 8 colors can be printed on one side of the tube film,
Alternatively, it is also possible to print four colors on each side.

By the way, when an attempt is made to continuously print patterns on the surface of the tube film by using two take-up rolls alternately using a flexographic printing machine, the tube film fed out from one roll body reaches the end portion. When unrolled, it is necessary to join the starting ends of the subsequent tube films unrolled from the other roll body (work roll switching work). Conventionally, when performing such a fabric switching operation, as shown in FIG. 8, the starting end of the succeeding tube film b is overlapped with the ending end of the preceding tube film a, and both tube films a are , B, a splicing splicing film c having a thickness of, for example, about 0.015 mm is arranged, and both ends of the splicing film c are joined to the tube films a and b to splice the tube films a and b. I was doing. In that case, the subsequent tube film b
The starting end of the sheet was sealed with the double-sided adhesive tape d, thereby preventing the printing film from being adversely affected by the inclusion of air in the tube film.

[0004]

However, in the above-described conventional tube film joining method, when different patterns are simultaneously printed on the left and right portions of one plate cylinder, the printing pressure of the plate cylinder is a normal tube. Since it is adjusted for the film, the tube film passing through the other side (for example, the left side portion) of the plate cylinder when the joint portion passes through one side (for example, the right side portion) of the plate cylinder is in a state in which no printing pressure is momentarily applied. However, printing defects will occur.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a tube film joining method capable of minimizing the occurrence of defective printing paper.

[0006]

SUMMARY OF THE INVENTION A tube film joining method according to the present invention is a method for joining a trailing end portion of a preceding tube film to a trailing end portion of a succeeding tube film at the time of switching a raw material in the printing of the tube film. The following tube film starting end is sealed at a predetermined part, and the tip side from the sealed part is 1
It is characterized in that it is cut into a single film portion, and this single portion is joined to the preceding tube film end portion.

[0007]

In the present invention, when switching the original fabric,
A predetermined portion of the starting end portion of the subsequent tube film is hermetically sealed by, for example, heat sealing adhesion, and the tip side from the sealing portion is cut into one film portion, and the one portion and the end portion of the preceding tube film are cut off. And are spliced directly or through a thin splicing film. By doing so, it is possible to prevent abnormal printing pressure when printing different patterns on the right and left portions of one plate cylinder at the same time, and thereby to minimize the occurrence of defective printing paper. can do.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments will be described below with reference to the drawings.

FIG. 1 is a perspective view showing a joint portion of a tube film according to an embodiment of the present invention, FIG. 2 is a sectional view showing the joint portion, and FIG. 3 is a perspective view showing an end portion of the tube film in the embodiment. FIG. 4 is a schematic configuration diagram of a flexographic printing machine for performing pattern printing on the tube film, and FIG. 5 is an enlarged view of a main part of FIG.

This embodiment is applied to the printing process of a packaging bag for a disposable diaper, and polyethylene is used as the tube film 1 as a material of the packaging bag, and this is used as a material.
It is formed into a tube shape to have a thickness of about 1 mm. As shown in FIG. 4, the tube film 1 is sequentially fed from the roll body 2 and supplied to the flexographic printing machine 3. Then, the printing machine 3 performs pattern printing on the front and back surfaces of the tube film 1. The flexographic printing machine 3 is a drum type (single-cylinder type), and is constructed by arranging four printing units 5, 5, 5, 5 of four colors around a large impression cylinder 4 in the center. is there. Each of the printing units 5, 5, 5, 5 includes a plate cylinder 6 that contacts the impression cylinder 4, a fountain roll 8 and an anilox roll 9 that supply the ink in the ink tray 7 to the plate cylinder 6, and the roll unit 2 is provided. The tube film 1 as an object to be printed, which has been fed from, passes sequentially through the printing units 5, 5, 5, 5 along the impression cylinder 4, thereby printing each color on the surface of the tube film 1. It Further, different patterns are formed on the right and left portions of the plate cylinder 6, respectively, and as shown in FIG. 5, the tube film 1 is temporarily passed through the left side portion of the plate cylinder 6 and one surface of the tube film 1 ( After printing on the surface), the tube film 1
Is reversed, the right side portion of the plate cylinder 6 is passed again, and printing is performed on the other surface (back surface).

Two rolls 2 are provided,
These two rolls 2 and 2 are supported by the roll support 10, and the tube film 1 fed from one roll 2 reaches the terminal end and is switched to the other roll 2 The starting end of the tube film 1 of the other roll body 2 is joined to the terminal end of the tube film 1.

A method for joining the tube films 1 will be described below with reference to FIGS. 1 and 2.

First, as a preparatory work, the starting end portion of the succeeding tube film 1 is separated from the end by a predetermined dimension and sealed by a heat seal portion 11 parallel to the edge, and a portion on the tip side of the heat seal portion 11 is sealed. The lower side is cut off to form one film portion 1a. Then, a splicing splicing film 12 having a thickness of about 12 to 15 μm, which is made of polyester and is cut into a trapezoidal shape, is prepared, and a double-sided adhesive tape 13 is provided on each back surface of the splicing film 12 at the front end and the rear end. Double-sided adhesive tape on the rear end 1
3 is attached to the upper surface of the one film portion 1a.

When the printing of the preceding tube film 1 is almost completed and the end portion of the tube film 1 is fed out from the roll body 2, the front end portion of the splicing film 12 is attached to the upper surface of the end portion, The tube film 1 and the splicing film 12 are joined by the double-sided adhesive tape 13. As a result, the leading tube film 1 and the trailing tube film 1 are joined together, and the tube film 1 can be continuously supplied to the flexographic printing machine 3.

According to this embodiment, for example, the tube film 1 has a film thickness of 0.1 mm, and the spliced film 1 is
When the film thickness of No. 2 is 0.015 mm and the thickness of the adhesive is neglected, the maximum thickness of the joint is 0.215 mm and the difference from the standard tube film 1 thickness of 0.2 mm is minimal ( It is possible to suppress it to 0.015 mm). Therefore, it is possible to minimize the shock when this joint portion passes through each printing unit 5, and the plate cylinder 6
It is possible to avoid adversely affecting the printing by the pattern on the other side. Further, according to this embodiment, since the starting end portion of the succeeding tube film 1 is sealed by the heat seal portion 11, it is possible to prevent air from being mixed into the tube film 1 at all. At the nip between the impression cylinder 4 and the plate cylinder 6, the tube film 1
It is possible to prevent wrinkles from occurring.

FIG. 6 is a sectional view showing a joint portion of a tube film according to another embodiment of the present invention.

In this embodiment, a sheet of film 1 formed at the beginning of a subsequent tube film 1 '.
The length of a'is made longer, and the leading end of the one film portion 1a 'is directly joined to the end portion of the preceding tube film 1'by a double-sided adhesive tape 13' without a joining film. ..

In the case of this embodiment, the maximum thickness of the joint is
When the thickness of the adhesive is ignored, the thickness becomes 0.3 mm, which is slightly thicker than that in the previous embodiment, but the same effect as that in the previous embodiment can be obtained.

FIG. 7 is a sectional view showing a modification of the other embodiment.

In this example, one film portion 1a 'is made to have the same length as that of the embodiment of FIG. 6, and the starting end portion of the succeeding tube film 1'is superposed on the end portion of the preceding tube film 1'. At the same time, a thin splice joint film 12 'is arranged so as to straddle both of these tube films 1'and 1'.
Both ends of 2'are joined to the respective tube films 1'and 1'by double-sided adhesive tapes 13 "and 13". Even with such a configuration, it is possible to obtain substantially the same effects as those of the above-described embodiment.

[0021]

Since the present invention is configured as described above, it is possible to reduce the thickness of the joint portion of the tube film, and in the case where different patterns are simultaneously printed on the left and right of one plate cylinder. Occurrence of abnormal printing pressure can be prevented, and as a result, the occurrence of defective printing paper can be minimized.

[Brief description of drawings]

FIG. 1 is a perspective view showing a joint portion of a tube film according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a joint portion of the tube film according to the above embodiment.

FIG. 3 is a perspective view showing an end portion of the tube film in the above embodiment.

FIG. 4 is a schematic configuration diagram of a flexographic printing machine according to the embodiment.

5 is an enlarged view of a main part of FIG.

FIG. 6 is a cross-sectional view showing a joint portion of a tube film according to another embodiment of the present invention.

FIG. 7 is a sectional view showing a modified example of the other embodiment.

FIG. 8 is a sectional view showing a conventional tube film joining method.

[Explanation of symbols]

 1,1 'Tube film 1a, 1a' One film part 11 Heat seal part 12, 12 'Splice splice film

Claims (1)

[Claims] 1. A method for joining a trailing end portion of a succeeding tube film to a trailing end portion of a preceding tube film at the time of switching the material in the printing of the tube film.
The trailing end of the following tube film is sealed at a predetermined portion, and the leading end side of the sealed portion is cut into one film portion, and this one portion is joined to the preceding tube film end portion. A method for joining tube films, characterized in that