JP2002241057A - Paper tube core, and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate generation of paper powder and effects of the external humidity, etc., on a paper tube from an outer circumferential surface and end faces of a paper tube core. SOLUTION: A cylindrical heat-shrinkable sheet 2 comprises an outer circumferential surface covering part 20 for covering the outer circumferential surface 30 of the paper tube 3, and end face covering parts 21 for covering end faces 31 of the paper tube 3. The outer circumferential surface 30 of the paper tube 3 is covered by the outer circumferential surface covering part 20, and the end faces 31 of the paper tube 3 are covered by the end face covering parts 21. In the core formed of the paper tube, the outer circumferential surface 30 of the paper tube 3 is covered by the outer circumferential surface covering part 20, and the end faces 31 of the paper tube 3 are covered by the end face covering parts 20. Thus, generation of paper powder not only from the outer circumferential surface 30 of the paper tube 3 but also from the end faces 31 is suppressed, and the effect by the change in the external humidity is considerably reduced. In particular, any separate countermeasures from that of the outer circumferential surface 30 need not be taken, and the outer circumferential surface 30 of the paper tube 3 and the end faces 31 of the paper tube 3 can be covered at the same time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper tube core and a method for manufacturing the same.

[0002]

2. Description of the Related Art Regarding a core used for winding a wire or a band-shaped product, a core made of a paper tube is less expensive to manufacture and dispose than a core made of another material. Since the cost of disposal is low, it is widely used. On the other hand, the core made of a paper tube is susceptible to external influences such as moisture absorption and drying during use (i.e., changes in length and diameter) iii) The core is impregnated in the core Iv) There is a danger of the transferred moisture being transferred to the product to be wound up. Iv) There is a seam on the outer peripheral surface because the band-shaped paper is wound into a tubular shape (steps affect winding up and wrinkles on the paper tube surface). Inviting the occurrence of the problem).

For this reason, during the production of the core, the surface of the paper tube is impregnated with a resin, and after the resin is cured, the surface of the paper tube is polished. Further, the end face of the paper tube was covered with a separate paper. As a result, the above problems i) to iv) were tentatively solved. But this is
This was a very labor-intensive task, and greatly affected the cost. This also means that when disposing of
This makes it difficult to carry out the treatment required for disposal and further makes it difficult to recycle.

Therefore, the inventor of the present invention has conducted research on the winding core, and in order to eliminate the above-mentioned trouble, before heating, the heat formed in a cylindrical shape having an inner diameter larger than the outer diameter of the paper tube. It was considered that a paper tube was placed in a shrinkable sheet, the heat-shrinkable sheet was shrunk by heating, and the heat-shrinkable sheet was applied to the outer peripheral surface of the paper tube to form a core made of a paper tube.

However, by forming the core made of a paper tube in this way, it is possible to prevent paper dust from being generated to some extent on the outer peripheral surface of the paper tube, to prevent the transfer of moisture to the product to be wound, Even if the outer peripheral surface can be smoothed, it is necessary to take measures against the end of the paper tube to prevent the generation of paper dust from the tube end, and the effect of external humidity on the paper tube through the tube end It won't come until you dispel. In this regard, as in the related art, since it takes time and effort to separately attach paper, as described above, the effect of reducing the time and effort by using the heat-shrinkable sheet cannot be sufficiently obtained.

[0006]

Therefore, the inventor of the present invention made further studies and made the present invention.
The above problems were solved.

[0007]

According to a first aspect of the present invention, there is provided a paper tube winding core comprising: a heat-shrinkable sheet 2 formed in a cylindrical shape;
The heat-shrinkable sheet 2 comprises a paper tube 3 whose outer peripheral surface 30 is covered, and has the following structure. That is, the tubular heat-shrinkable sheet 2 has the outer peripheral surface covering portion 20 that covers the outer peripheral surface 30 of the paper tube 3 and the end surface covering portion 21 that covers the end surface 31 of the paper tube 3. The outer peripheral surface 30 of the paper tube 3 is covered with the outer peripheral surface covering portion 20, and the end surface 31 of the paper tube 3 is covered with the above-described end surface covering portion 21.

In the core for a paper tube according to the first aspect of the present invention having such a configuration, the outer peripheral surface 30 of the paper tube 3 is covered with the outer peripheral surface covering portion 20 and the paper tube core is covered by the end surface covering portion 21. 3
Since the end face 31 is covered, it is possible to suppress the generation of paper dust from the end face 31 as well as the outer peripheral face 30 of the paper tube 3. Further, by shielding the outer peripheral surface 30 of the paper tube 3 as well as the end surface 31 thereof from the outside, the influence of a change in external humidity is significantly reduced. In particular, since the heat-shrinkable sheet 2 is provided with the end face covering portion 21, it is not necessary to take any additional measures to obtain the above-described effect on the end face 31 of the paper tube 3, and the outer circumferential surface 30 of the paper tube 3 is covered. At the same time, the end face 31 of the paper tube 3 can be coated at a time.

In the core made of a paper tube according to the second invention of the present application,
In the core made of a paper tube according to the first aspect of the present invention, the tube end covering portion 21 has an inner peripheral surface covering portion 2 along an inner peripheral surface 32.
2 is provided.

[0010] The paper tube core according to the second aspect of the present invention having such a configuration has the function of the paper tube core according to the first aspect of the present invention, and has the inner peripheral surface covering portion 22. Since the inner peripheral surface 32 of the paper tube 3 is also covered, the inner peripheral surface 32 of the paper tube 3 can be suppressed from generating paper dust in the same manner as described above. Could be suppressed by the change of. In addition, since the coating of the inner peripheral surface 32 of the paper tube 3 can be performed together with the coating of the outer peripheral surface 30 of the paper tube 3, no extra work is required.

The method for manufacturing a paper tube core according to the third invention of the present application is directed to a method for manufacturing a paper tube core according to the third invention of the present application, wherein the inner diameter is larger than the outer diameter of the paper tube 3 before heating. The paper tube 3 is arranged in a heat-shrinkable sheet 2 formed in a tubular shape having the shape shown in FIG.
The heat-shrinkable sheet 2 is attached to the sheet No. 0 and has the following configuration. That is, in this method, before heating, the tubular heat-shrinkable sheet 2 is longer than the paper tube 3, and the above-described heating causes the diameter and length of the heat-shrinkable sheet 2 to shrink. The end surface 31 of the paper tube 3 together with the outer peripheral surface 30 of the paper tube 3
Is covered with a heat-shrinkable sheet 2.

By adopting such a configuration, the method for manufacturing a paper tube core according to the third invention of the present application provides specific means for obtaining the paper core according to the first invention. This has made it possible to significantly reduce the time and effort for coating the paper tube 3. That is, the method according to the present invention is:
By using the heat-shrinkable sheet 2, the outer peripheral surface 3 of the paper tube 3
0 and a covering portion of the end face 31 can be provided.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment of the present invention. FIG. 1A is a schematic longitudinal sectional view of a paper core 1 according to the present invention, and FIG. 1B is a schematic perspective view showing a process of manufacturing the paper core 1. . FIG. 2 (A) (B)
1 is a schematic longitudinal sectional view showing one process of manufacturing the paper core 1. FIG. 3 is a schematic perspective view showing a method of manufacturing the paper tube of FIG.

A core 1 made of a paper tube according to the present invention comprises a heat-shrinkable sheet 2 formed in a tubular shape and a paper tube 3 whose outer peripheral surface 30 is covered with the heat-shrinkable sheet 2. It has the following configuration. That is, the cylindrical heat-shrinkable sheet 2 includes an outer peripheral surface covering portion 20 that covers the outer peripheral surface 30 of the paper tube 3,
It has end face covering portions 21 and 21 that cover the end faces 31 and 31 of the paper tube 3. The outer peripheral surface 30 of the paper tube 3 is
0, and both end faces 31, 31 of the paper tube 3 are covered with the end face covering portions 21, 21. The paper core 1 is suitable for winding various products as a core, and is particularly suitable for winding a resin film or a non-ferrous metal foil. These products especially dislike paper powder, and in this regard, the core 1 made of a paper tube according to the present invention is optimal. Hereinafter, the configuration of each unit will be described in detail.

The paper tube 3 is formed by laminating paper to form a tubular body. That is, the paper tube 3 is made of a paperboard formed in a tubular shape, and the inner peripheral surface 32 thereof is
It is desirable to use a laminated paper that can be recycled.

The heat-shrinkable sheet 2 is made of a polyester, vinyl chloride, polyethylene, polypropylene, or other heat-shrinkable film and formed into a seamless (seamless) cylindrical shape.

As shown in FIG. 1 (A), the end face covering portions 21 and
Reference numeral 21 denotes a portion extending from the end of the outer peripheral surface covering portion 20 of the tubular heat-shrinkable sheet 2 toward the center x of the core 1 made of a paper tube. It does not appear on the center x side of the inner diameter. In this embodiment, the end face covering portions 21 and 21 are formed in a planar shape, respectively.
, But not the inner peripheral surface 32 of the paper tube 3. In order to wind up a product using the core 1 made of a paper tube, the core 1 made of a paper tube is fixed to a rotating shaft (not shown) (fitted to the outer periphery of the rotating shaft). By forming, the end surface covering portions 21 and 21 do not contact the rotating shaft, and the end surface covering portions 21 and 21 do not hinder the mounting of the paper core 1 on the rotating shaft.

Next, a description will be given of a method of manufacturing the above-mentioned core 1 made of a paper tube. In the method of manufacturing the above-mentioned core 1 made of a paper tube, before heating, the paper tube 3 is arranged in a tubular heat-shrinkable sheet 2 having an inner diameter larger than the outer diameter of the paper tube 3, and heat is applied by heating. The heat-shrinkable sheet 2 is attached to the outer peripheral surface 30 of the paper tube 3 by shrinking the shrinkable sheet 2, and has the following configuration. That is, before heating, the tubular heat-shrinkable sheet 2 is
By heating such a heat-shrinkable sheet 2, the heat-shrinkable sheet 2 reduces its diameter and length (in the axial direction), and covers the outer peripheral surface 30 of the paper tube 3. At the same time, when the heat-shrinkable sheet 2 comes into contact with the outer peripheral surface 30 of the paper tube 3, the portion of the heat-shrinkable sheet 2 protruding from the tube end of the paper tube 3 is bent toward the center of the paper tube 3. In such a state, the protruding portion also contracts. Thus, after heating and shrinking, the heat-shrinkable sheet 2 constitutes the outer peripheral surface covering portion 20 that covers the outer peripheral surface 30 of the paper tube 3, and the protruding portion of the heat-shrinkable sheet 2 is changed to the end surface covering portion. 21 and 21 are configured. Hereinafter, a method for manufacturing the paper core 1 will be described in more detail.

As shown in FIG. 1 (B), the outer side of the paper tube 3 is concentric with the paper tube 3 (the tubular heat-shrinkable sheet 2).
(The center of the paper tube 3 coincides with the center of the paper tube 3), and the heat-shrinkable sheet 2 before heating, which is formed in a tubular shape, is arranged. In the state before heating, the length w1 (axial width) of the tubular heat-shrinkable sheet 2 is larger than the length v1 (axial width) of the paper tube 3. The diameter w2 (width in the direction perpendicular to the axis) of the tubular heat-shrinkable sheet 2 is also larger than the outer diameter v2 of the paper tube 3.

With respect to the diameter w2 of the heat-shrinkable sheet 2, the inner peripheral surface of the heat-shrinkable sheet 2
Is set so as to abut on the outer peripheral surface 30. Regarding the length w1 of the heat-shrinkable sheet 2 before heating, the paper tube 3
Is longer than the length v1, but as described above, the inner peripheral surface of the heat-shrinkable sheet 2 is
Is longer than the length v1 of the paper tube 3 even when it comes into contact with the paper tube 3. That is, as shown in FIG.
The heat-shrinkable sheet 2 includes a heat-shrinkable sheet 2 during heat shrinkage.
Is in contact with the outer peripheral surface 30 of the paper tube 3,
The protruding portion 21 protruding from the outer peripheral surface 30 of the paper tube 3
a and 21a are set. By heating, FIG. 2 (B)
As shown in FIG. 5, the protruding portions 21a, 21
a is bent toward the center xx direction of the paper tube 3, and finally, the protruding portions 21 a, 21 a become the end surfaces 31,
31 and comes into the state shown in FIG. That is, the protruding portions 21a, 21a become the end face covering portions 21, 21 due to the heat shrinkage. Extrusion sites 21a, 2
It is preferable that dimensions of 1a be set in advance as the end face covering portions 21 and 21 so as to be substantially the same as the inner diameter v3 of the paper tube 3.

Specifically, the length w1 of the heat-shrinkable sheet 2 before heating has a margin (interval p, p) with respect to each of the front and rear of the paper tube 3 and is equal to the length v1 of the paper tube 3. Regardless, it is appropriate that each of the intervals p is approximately 50 mm. Further, for example, when the outer diameter v2 of the paper tube 3 is 100 mm, it is appropriate that the diameter w2 of the heat-shrinkable sheet 2 before heating is about 115 mm. As described above, the allowances (intervals p, p) are set such that the above-mentioned protruding portions 21a, 21a can be secured even when the heat-shrinkable sheet 2 is shrunk in the axial direction.

When used as a core for winding a product as described above, the outer diameter v2 of the paper tube 3 is 80 mm, 102 mm, 152.6 mm, 180 m in addition to the above 100 mm.
Generally, a value such as m or 204 mm is adopted. However, regardless of the outer diameter v2, the inner diameter v3 of the paper tube 3 generally has a value of about 76.2 mm in common. In this regard, when the product is wound as a core, the outer diameter of the rotating shaft on which the core 1 made of paper tube is mounted is 7 mm.
This is because a value of 6.2 mm is adopted. However, these numerical values can be changed as needed.

As for the heating method required for the above-mentioned heat shrinkage, as shown in FIG.
And heat. It is preferable to rotate the heat-shrinkable sheet 2 and the paper tube 3 so that the heat is evenly distributed during heating. However, if unnecessary, the rotation can be performed without performing such rotation. Particularly, a method of blowing hot air on the heat-shrinkable sheet 2 is preferable as such a heating method. However, the method of heating is not limited to such a method, and the present invention can be implemented by heating the heat-shrinkable sheet 2 using another heating method. The method of using the above-mentioned hot air as a heating method will be specifically described. The heat-shrinkable sheet 2 arranged as shown in FIG. At this time, as described above, the heat-shrinkable sheet 2
The paper tube 3 is passed through the hot blast stove 4 while rotating.
Thereby, the heat-shrinkable sheet 2 is heated. As shown in FIG. 3, the hot blast stove 4 includes a moving table 42 such as a conveyor capable of moving the hot blast furnace 4 in the horizontal direction, and a moving table 4.
A holding rod 40 extending horizontally on the moving table 42; and supporting legs 4 provided on the moving table 42 and supporting the holding rod 40 on the moving table 42.
1, 41 are provided. The paper tube 3 and the heat-shrinkable sheet 2 are passed through the holding rod 40, and the paper tube 3 and the heat-shrinkable sheet 2 are supported by being suspended from the holding rod 40. The holding rod 40 is rotatable with power (the power source is not shown).
The supporting paper tube 3 and the heat-shrinkable sheet 2 can be rotated (the heat-shrinkable sheet 2 indirectly obtains a rotational force from the holding rod 40 through the paper tube 3). In this state, the moving table 42 is operated to move the heat-shrinkable sheet 2 and the paper tube 3 in the hot stove 4 while holding the holding rod 40.
By rotating, each part of the heat-shrinkable sheet 2 and the paper tube 3 can be uniformly heated. In the furnace,
If uniform heating is possible without any special measures, the rotation during this movement can be performed without performing. By the above-described heating, the heat-shrinkable sheet 2 contracts in the radial direction and the length direction, and adheres to the surface of the paper tube 3 through the process shown in FIG. That is, by heat shrinkage of the heat-shrinkable sheet 2, the outer peripheral surface covering portion 20 and the end surface covering portion 21 are formed, and the outer peripheral surface 30 of the paper tube 3 is covered with the outer peripheral surface covering portion 20. End face 31 of paper tube 3
Is coated. The inner diameter w3 of the end face covering portion 21 may be set in advance so as to be substantially the same as the inner diameter v3 of the paper tube 3. However, if not set in this way, or if the diameter becomes smaller than the inner diameter v3 of the paper tube 3 after the heat shrinkage due to an error, that is, if it protrudes from the end surface 31 of the paper tube 3 toward the center x, this protrudes. Cut out part. Thus, the inner diameter v3 of the paper tube 3 and the inner diameter w3 of the end face covering portion 21 are made to match.

Prior to the heating, it is preferable to apply a slightly adhesive resin to the outer peripheral surface 30 and the end surfaces 31, 31 of the paper tube 3. When the heat-shrinkable sheet 2 is adhered to the outer peripheral surface 30 and the end surfaces 31 of the paper tube 3 by the above-described heat shrinkage, the heat-shrinkable sheet 2 can be securely fixed to the paper tube 3. This is because, during use of the core 1 made of a paper tube, the heat-shrinkable sheet 2 does not idle with respect to the paper tube 3 and the product can be taken up reliably.

The core 1 made of the paper tube thus formed
Has the following advantages. 1) During use, a situation in which paper dust is generated from the outer peripheral surface 30 and the end surface 31 of the paper tube 3 can be suppressed. 2) With respect to the outer peripheral surface 30 and the end surface 31 of the paper tube 3, which are particularly susceptible to external influences such as moisture absorption and drying, the effects were eliminated, and the expansion and contraction of the dimensions of the paper tube could be significantly reduced. 3) The moisture in the paper tube 3 is not transferred to a product for winding. 4) Since the core 1 made of a paper tube has a smooth and robust surface,
No wrinkles or deviations occur during winding. In particular, since the paper tube 3 is covered with the tubular seamless heat-shrinkable sheet 2, the winding surface (paper tube outer peripheral surface) is made smooth (to eliminate a step at the paper joint). There is no need to take a separate method. 5) After using the core 1 made of a paper tube, the heat-shrinkable sheet 2 is
The paper tube 3 and the heat-shrinkable sheet 2
It can be used as a raw material, making waste disposal efficient and easy to recycle. In particular, in the present invention, in order to obtain the effects 1) to 5) described above, it is possible to complete the processing to be performed on the outer peripheral surface 30 and the end surface 31 of the paper tube 3 at a stroke, and such effects can be easily achieved. Made it possible to obtain. In other words, in order to obtain the above-described effect on the end surface 31 of the paper tube 3, it is not necessary to take any other measures separately from the outer peripheral surface 30. The coating can be performed at a time. Also, by coating the end face 31 of the paper tube 3, the effects 1) to 5) described above can be obtained more reliably.

With reference to Table 1 and FIG. 4, the effect of the above 2), which excludes external influences such as moisture absorption and drying, will be specifically described.

[0027]

[Table 1]

Table 1 shows that the core 1 made of a paper tube of the present invention, that is, the paper tube 3 is covered with the heat-shrinkable sheet 2 as described above with respect to the change in the length and the outer diameter of the core due to the change in temperature and humidity. The data (data indicated as “covered ants”) and the data not subjected to such coating (data indicated as “covered pear”) are compared. The test items are the water content, length, and outer diameter of the core to be tested. Regarding the paper tube, the inner diameter of both the product of the present invention and the comparative example is 76.2.
mm, a thickness of 10 mm (outer diameter 96.2 mm) and a length (in the axial direction) of 1000.0 mm. The base paper used for the paper tube was a B class-0.8 base. The temperature and humidity of the atmosphere were set to 20 ° C., 30 ° C. and 40 ° C., and the humidity was adjusted to 30% RH and 60% RH, respectively.
And 90% RH, and the adjustment time was 24 hours.
The RH indicates a relative humidity.

From Table 1, when the ambient humidity is 30% RH,
There is no change in the axial length of the paper core of the present invention and the paper core of the comparative example. However, if the humidity is 60% R
In the case of H and 90% RH, in the paper core of the core according to the present invention, only a slight elongation in the range of 1.0 mm or less was recognized and there was almost no change, whereas the paper core of the comparative example was hardly changed. In the figure, the extension of the length is recognized at a value one order of magnitude larger than the paper tube of the present invention. Also, the outer diameter of the paper core of the core according to the present invention changes only within a range of ± 0.1 mm even when the humidity increases, and it can be said that the outer diameter hardly changes.
On the other hand, in the paper tube of the comparative example, as compared with the paper tube of the present invention, a change in an order of magnitude larger than that of the paper tube according to the humidity is observed. Regarding the water content, both the paper core of the core according to the present invention and the paper core of the comparative example tend to increase as the humidity increases, but no clear difference is observed between them.

4A is a graph showing the relationship between the water content and the length of the paper tube. The vertical axis shows the length (mm), and the horizontal axis shows the water content (%). Is shown. In the graph 100, those having square dark dots are covered with the heat-shrinkable sheet 2 according to the present invention, and those having white rhombic dots are covered with the heat-shrinkable sheet 2. Not a comparative example. FIG.
(B) 101 is a graph showing the relationship between the water content and the outer diameter of the paper tube, where the vertical axis shows the outer diameter (mm) of the paper tube and the horizontal axis shows the water content (%). . Graph 101
Are those having dark square dots covered with the heat-shrinkable sheet 2 according to the present invention, and those having white rhombic dots are not covered with the heat-shrinkable sheet 2 This is a comparative example.

As shown in FIG. 4A, in the paper tube of the comparative example, an increase in the length in the axial direction is observed in the paper tube of the comparative example due to the increase in the water content. No change was observed. FIG.
As shown in (B), in the paper tube of the comparative example, it is recognized that the outer diameter is enlarged so as to rise to the right due to the increase of the water content, but in the paper tube of the present invention, the outer diameter is flattened and a large change is observed. It is not allowed.

In the above embodiment, in order to smoothly attach the core to the rotating shaft when using the core, FIG.
As shown in (A), the end face coating portions 21 and 21
Only the end face 31 is covered. In addition, in order to further enhance the above-described effect, as shown in FIG. 5, the inner peripheral surface covering portion 22 that covers a part of the inner peripheral surface 32 of the paper tube 3 is replaced with the end surface covering portion 2.
It is also possible to carry out the present invention by providing them at 1, 21. this is,
The inner peripheral surface 32 of the paper tube 3 is retracted from the inner diameter portions of the end surface covering portions 21 and 21 into the paper tube 3. That is, the paper core 1 is made of a heat-shrinkable sheet 2 formed in a tubular shape.
And a paper tube 3 whose outer peripheral surface 30 is covered with the heat-shrinkable sheet 2. The tubular heat-shrinkable sheet 2 has an outer periphery that covers the outer peripheral surface 30 of the paper tube 3. Surface coating 20
An end face covering portion 21 for covering the end face 31 of the paper tube 3;
And an inner peripheral surface covering portion 22 that covers the inner peripheral surface 32 of the inner peripheral surface. The outer peripheral surface 30 of the paper tube 3 is covered with the outer peripheral surface covering portion 20, the end surface 31 of the paper tube 3 is covered with the above-mentioned end surface covering portion 21, and the inner peripheral surface 32 of the paper tube 3 is covered with the inner surface 32. It is covered with the peripheral surface covering portion 22.

As in the present embodiment, the inner peripheral surface 32 of the paper tube 3 is also covered with the heat-shrinkable sheet 2 in the vicinity of the opening 33 so that the above-described generation of paper dust and external It is possible to further suppress the influence of humidity and the like. However, when the winding core is attached to the rotating shaft in use, it is more advantageous that the core does not have the inner peripheral surface covering portion 22 as in the embodiment shown in FIG. On the other hand, in order to more reliably prevent the generation of paper dust in the vicinity of both ends of the inner peripheral surface 32 of the paper tube 3, it is better to provide the inner peripheral surface 32 of the paper tube 3 with a covering portion as shown in FIG. It is advantageous.

A method of manufacturing the core made of a paper tube according to the embodiment of FIG. 5 will be described with reference to FIG. FIG. 6 (A)
As shown in FIG. 5, a hot air stove 4 similar to that shown in FIG. 3 is used to form the paper core shown in FIG. That is, the holding rod 4 passed between the support legs 41 on the movable table 42.
At 0, it is held through the paper tube 3 and the heat-shrinkable sheet 2.
By operating the moving table 42, the paper tube 3 and the heat-shrinkable sheet 2 are moved in the hot blast stove 4 while moving.
The paper tube 3 and the heat-shrinkable sheet 2 are rotated by the rotation of the holding rod 40. However, in this embodiment, during the formation of the end face covering portion 21, it is necessary to form the inner peripheral surface covering portion 22.
Since a portion that protrudes toward the center from the end surface covering portion 21 (protruding portion 21 a) is generated, the holding rod 40 hinders the formation of the inner peripheral surface covering portion 22. Therefore, in this embodiment, the spacer 5 is provided on the holding rod 40 so that a portion necessary for forming the inner peripheral surface covering portion 22 does not contact the holding rod 40. The spacer 5 includes a holding rod 40
Is a columnar portion having a diameter larger than that of the holding rod 40 provided on the side peripheral surface of the inner peripheral surface covering portion 22,
22 so as not to reach the inner peripheral surface covering portion 22 during and after the formation of the inner peripheral surface covering portion 22 (in FIG. Spacer 5
Does not coincide with the center of the paper tube 3. However, it is also possible to carry out the method by aligning the center of the columnar spacer 5 with the center of the paper tube 3. In particular, by making the columnar spacer 5 concentric with the paper tube 3, that is, by making the outer diameter of the spacer 5 substantially coincide with the inner diameter of the paper tube 3, the spacer 5
The stability of the position of the paper tube 3 with respect to is increased.) Spacer 5
Rotates with the rotation of the holding rod 40. The paper tube 3 and the heat-shrinkable sheet 2 are held away from the holding rod 40 by being separated upward. Difference in radius between spacer 5 and holding rod 40, holding rod 40
, The paper tube 3 and the heat-shrinkable sheet 2 can be separated upward. Therefore, the difference in radius between the spacer 5 and the holding rod 40 is
The width of the protruding portion 21a is set to be larger than the width extending to the center x side of the portion to be the inner peripheral surface covering portion 22.

Next, a method of forming the inner peripheral surface covering portion 22 after forming the end surface covering portion 21 will be described. As shown in FIG. 6 (B), the formation of the above-mentioned end face covering portion 21 allows the formation of FIG.
As in the case shown in (B), the protruding portion 21a contacts the end faces 31, 31 of the paper core 3. In this embodiment, the protruding portion 21 a constitutes the end surface covering portion 21 and the inner peripheral surface covering portion 22. Therefore, the paper tube 3 end face 3
The protruding portion 21 a protrudes from the end faces 31, 31 even after contacting the end faces 31, 31. Hot air N is again applied to the protruding portion of the protruding portion 21a to make this portion easily deformable. Then, this portion is bent into the paper tube 3 by the pressing device 6 to form the inner peripheral surface covering portion 22.
As shown in FIG. 6C, by moving the pressing device 6 from the outside of the paper tube 3 to the inside of the paper tube 3, the protruding portion 21 is formed.
The protruding portion of a is pressed by the pressing device 6 and bent inside the paper tube 3. 6B to 6F, the left side is the traveling direction (forward) of the pressing device 6, and the right side is the retreating direction (rearward) of the pressing device 6. Pressing device 6
The pressing device 6 is formed smaller than the inner diameter of the paper tube 3 so that the protruding portion can be smoothly folded into the paper tube 3. Face 32
There is a gap between. Therefore, since the protruding portion is completely covered with the inner peripheral surface 32 of the paper tube 3 as the inner peripheral surface covering portion 22, the outer peripheral surface of the pressing device 6 is (part of the side surface 60) of the pressing device 6. Is formed so as to be able to expand. When the pressing device 6 is inserted into the paper tube 3, FIG.
6C, the side surface of the pressing device 6 is made small, and after insertion, as shown in FIG. 6D, the side surface of the pressing device 6 is expanded in the sheet gap 3 to remove the protruding portion. , To the inner peripheral surface 32 of the paper tube 3. In this way, during the heat shrinkage, the protruding portion of the protruding portion 21a is connected to the inner peripheral surface 32 of the paper tube 3.
To follow. The protruding portion is replaced with the inner peripheral surface covering portion 22.
As shown in FIG.
As shown in (E), the side surface of the expanded pressing device 6 is retracted, and as shown in FIG. 6 (F), the pressing device 6 is retracted and taken out of the paper tube 3. Thus, the core made of a paper tube shown in FIG. 5 is completed. When the operation by the pressing device 6 is performed on the holding bar 40, an insertion hole (not shown) through which the holding bar 40 is inserted is formed in the pressing device 6. That is, the holding rod 40 is inserted through the pressing device 6, the pressing device 6 can be moved along the holding rod 40, and the pressing device 6 can be moved in and out of the paper tube 3.

An appropriate mechanism for expanding the side surface of the pressing device 6 will be described with reference to FIG. FIG. 7 (A)
7 is a schematic longitudinal sectional view of the pressing device 6 in a state where the split mold 60 is closed, FIG. 7 (B) is a schematic transverse sectional view thereof, and FIG. 7 (C) is a pressing device in a state where the split mold 60 is expanded. 6 is a schematic cross-sectional view, and FIG. 7D is a schematic cross-sectional view thereof. FIG. 6 (B)-
7 (A) and 7 (C), the left side is the traveling direction (forward) of the pressing device 6 during insertion, as in (F). The right side is the retreating direction (rearward) of the pressing device 6. This pressing device 6
A cylindrical main body 63; and a main body 6 housed inside the main body 63.
3 and a split piece 61
.. 61 are provided. Pressing body 62
Has a triangular pyramid taper at its front. Pressing device 6
Is moving forward or backward inside the paper tube 3, as shown in FIG. 7 (A), the pressing body 6 is located in the rear of the main body 63 (on the right side in FIG. 7 (A)). , Body 63
It does not protrude laterally (up and down in FIG. 7A) from the outer peripheral surface. However, as shown in FIGS. 6C and 6D, when the pressing device 6 enters into an appropriate position inside the paper tube 3, the pressing body 62 is moved relative to the main body 63 in the direction of movement of the pressing device 6 (FIG. The pressing means 62 is moved toward the left side in (A) (moving means of the pressing body 62 with respect to the main body 63 is not shown, but is implemented by adopting a well-known mechanism). At this time, the taper of the pressing body 62 presses the split mold pieces 61. As a result, as shown in FIGS.
1 ... 61 project from the outer peripheral surface (side surface) of the main body 63. That is, the split mold 60 is radially expanded from the pressing device 6 by the sliding of the pressing body 62 in the main body 63. As a result, each of the split pieces 61... 61 of the split mold 60 presses the protruding portion of the above (FIG. 6D) against the inner peripheral surface 32 of the paper tube 3, and the protruding portion of the protruding portion 21 a is It is made to follow the inner peripheral surface 32 of the tube 3. After the protruding portion is completely covered with the inner peripheral surface 32 of the paper tube 3 as the inner peripheral surface covering portion 22, the pressing body 62 is retracted rightward with respect to the main body 63 to the original position (FIG. 7 (A). As a result, the split mold pieces 61... 61 from which the pressing from the pressing body 62 has been released are retracted to the original state (FIGS. 6E and 7A). With this, paper tube 3
On the other hand, the pressing device 6 can be retracted, and the pressing device 6 can be taken out of the paper tube 3. In the above, the split mold pieces 61... 61 constitute a part of the outer peripheral surface of (the main body 63 of) the pressing device 6. However, all split pieces 61 ... 61
Can be implemented even if it constitutes the entire outer peripheral surface (side surface) of (the main body 63 of) the pressing device. Further, a mechanism for expanding the pressing device 6 can be implemented by adopting a mechanism other than the above. Further, in this embodiment, the heat-shrinkable sheet 2 is heated by rotating the heat-shrinkable sheet 2. However, if it is unnecessary, the heat-shrinkable sheet 2 can be heated without such rotation. In addition, in both the above case and the case shown in FIG. 3, when the heat-shrinkable sheet 2 is not rotated, the structure for rotating the holding rod 40 is not required, so that the apparatus can be simplified.

In order to obtain the core made of a paper tube according to the embodiment shown in FIGS. 1 and 5, each of them heats the heat-shrinkable sheet 2 by blowing hot air using a hot blast stove. did. However, as a method of heating the heat shrinkable sheet 2,
In any case including the case of reheating, the present invention is not limited to such a means. For example, the heat-shrinkable sheet 2 disposed around the paper tube 3 may be directly brought close to a heater, immersed in warm water or the like. Method, or a method using electromagnetic waves or ultrasonic waves, and other electric methods, such as an optical method such as a laser, etc. It is possible.

[0038]

According to the first aspect of the present invention, it is possible to suppress the generation of paper dust not only from the outer peripheral surface of the paper tube core but also from the end surface of the paper tube core. In addition, the effect of changes in external humidity was significantly reduced. In particular, in order to obtain the above-mentioned effect, it is not necessary to take a separate and troublesome means with respect to the outer peripheral surface of the paper tube. Also,
The same effect can be obtained.

By implementing the second invention of the present application, it is possible to obtain the same effects as the first invention of the present application, and also to suppress the generation of paper dust on the inner peripheral surface of the paper tube in the same manner as described above. In addition, the influence of the change in external humidity could be suppressed. In addition, the inner peripheral surface of such a paper tube can be implemented together with the implementation of the measures taken to obtain the above-mentioned effect on the outer peripheral surface of the paper tube, similarly to the end surface of the paper tube, and additional work is required. And not.

By implementing the third invention of the present application, specific means for obtaining the core of the paper tube according to the first invention of the present application can be provided, and the winding of the paper tube according to the first invention of the present application can be provided. The core can be obtained easily.

[Brief description of the drawings]

FIG. 1A is a schematic vertical sectional view of an embodiment of the present invention, and FIG. 1B is a schematic perspective view showing one process of manufacturing the same.

FIGS. 2A and 2B are schematic vertical cross-sectional views each showing a manufacturing process of the embodiment.

FIG. 3 is a schematic perspective view showing a state in which the core of the paper core shown in FIG. 1 is being manufactured.

FIG. 4A is an explanatory diagram showing the relationship between the water content and the length of a paper tube for the above-described embodiment of the present invention and a paper tube not covered as a comparative example, and FIG. It is explanatory drawing which shows the relationship between the water content of a paper tube, and an outer diameter about the said embodiment of this invention, and the paper tube which is not covered as a comparative example.

FIG. 5 is a schematic vertical sectional view showing another embodiment.

6A is a schematic perspective view showing one step of a method of manufacturing the paper core shown in FIG. 5; FIG. It is an end view, (C) is a principal part schematic end view which shows one process of manufacture following (B),
(D) is a principal part schematic end view which shows one process of manufacture following (C), (E) is a principal part schematic end view which shows one process of manufacture following (D), (F) is It is a principal part approximate end view which shows one process of manufacture following (E).

FIG. 7A is a pressing device 6 shown in FIGS. 6B to 6F.
(B) is a schematic cross-sectional view thereof,
(C) is a schematic longitudinal sectional view showing the expanded state of the pressing device 6, and (D) is a schematic transverse sectional view thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Paper core core 2 Heat shrinkable sheet 3 Paper core 20 Outer surface coating part 21 End surface coating part 22 Inner surface coating part 30 Outer peripheral surface (of paper core 3) 31 End surface (of paper core 3) 32 (paper core) 3) Inner circumference

Claims (3)

[Claims] 1. A heat-shrinkable sheet (2) formed in a cylindrical shape.
And a paper core (3) whose outer peripheral surface (30) is covered with the heat-shrinkable sheet (2). An outer peripheral surface covering portion (20) covering an outer peripheral surface (30) of the paper tube (3), and an end surface covering portion (21) covering an end surface (31) of the paper tube (3); ) Is coated with the outer peripheral surface coating portion (20), and the end surface (31) of the paper tube (3) is coated with the end surface coating portion (21). Core made of paper tube. 2. An inner peripheral surface (32) is provided on the pipe end covering portion (21).
The core according to claim 1, further comprising an inner peripheral surface covering portion (22) along the inner peripheral surface. 3. A heat-shrinkable sheet (2) formed into a tubular shape having an inner diameter larger than the outer diameter of the paper tube (3) before heating.
(3), and heat-shrinkable sheet (2) is shrunk by heating to apply heat-shrinkable sheet (2) to outer peripheral surface (30) of paper tube (3). In the method, before heating, the tubular heat-shrinkable sheet (2) is longer than the paper tube (3), and
By reducing the diameter of (2) and its length, a paper tube (3)
A method for producing a core for a paper tube, characterized in that the end surface (31) of the paper tube (3) is coated with a heat-shrinkable sheet (2) together with the outer peripheral surface (30) of the paper tube.