JP2589254B2 - Dandy roll for black watermark and production method thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Object of the invention]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dandy roll used for providing a watermark pattern in papermaking and a method for producing the same.

[0002]

BACKGROUND OF THE INVENTION Watermark patterns provided on paper include a black watermark and a white watermark. In the black watermark, the watermark pattern portion looks darker than the surroundings, while in the white watermark, the watermark pattern portion appears through. Things. In any case, the thickness or density of the stock web is changed in the papermaking stage to develop a watermark pattern.

[0003] Several methods have been developed for such a method. However, in a wire part during a papermaking process, a device provided with a water-permeable holding net called a dandy roll on the roll surface is a paper material. There has been proposed a method of acting on the web and giving a change in basis weight such as a change in thickness or density to a part of the stock web by unevenness having a shape corresponding to the pattern provided on the surface of the dandy roll. The technical points required for forming such a watermark include that the watermark is clearly expressed and that the watermark can be stably processed during papermaking.

Incidentally, a dandy roll net for producing general paper has a wire diameter of 234 to 295 μm and a diameter of 40 to 6 μm.
Although a mesh of 0 mesh is used, in the case of such a net, the edge portion of a pattern or a character is not sharp.

[0005] Therefore, as a device for sharpening the edge portion of a pattern or a character, a method of increasing the number of meshes of the mesh to reduce the distance between the filaments, or reducing the filament of the mesh can be considered. However, the former method has a problem that the dandy roll is stained, and the latter method has a problem that the net is likely to swell, scratch, or deform.

[0006]

[Technical Issues Attempted to Be Developed] The present invention has been made in view of such a background. In forming a black watermark, the inventor of the present invention has made clear the edges of the black watermark design and characters. A new attempt was made to develop a new dandy roll for black watermark and a method for producing the same.

[0007]

Configuration of the Invention

The dandy roll for black watermark according to the first invention of the present application has a dandy roll whose surface is formed by a concave-shaped net roll having a recess for forming a black watermark. Wherein the concave portion and the outer surface around the concave portion are polished by 15 to 30% of the diameter of a filament constituting the concave-shaped mesh roll.

The dandy roll for black watermark according to the second invention of the present application is characterized in that, in addition to the above requirements, the dandy roll is chrome-plated.

Further, a third invention, a method for manufacturing a dandy roll for black watermark, according to the present invention, is a press-formed flat mesh using a die to form a concave portion for forming a black watermark. In the method of manufacturing a dandy roll by winding this concave-shaped flat mesh around a lower net roll, prior to press-forming the flat net, the position of the concave portion in the flat net is determined in advance by the filament forming the flat net. 15 ~
It is characterized by being polished by 30%. It is an object of the present invention to achieve the above object.

[0010]

According to the present invention, the concave portion of the concave-shaped net roll of the dandy roll and the outer surface constituting the periphery thereof are polished by 15 to 30% of the diameter of the filament constituting the concave-shaped net roll. Therefore, the smoothness of each surface constituting the recess is improved and the diameter of the filament is reduced. Therefore, in the black watermark made by using such a concave-shaped shaping net roll, the edges of the design and the character become clear.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. Reference numeral 1 denotes a dandy roll to which the present invention is applied. As shown in FIG. 1, the dandy roll passes a center axis 3 through an axis of a roll main body 2 as an example, and a disc is provided at regular intervals on the center axis 3. 4 is provided to form a body, thereby adopting a structure for supporting the roll body 2. The roll body 2 includes a lower net roll 5 provided directly on the disk 4 and a concave-shaped net roll 6 provided on the lower net roll 5.

The concave-shaped netting roll 6 is used to form a black watermark by acting on the stock web, and this filament roll has a filament diameter of, for example, 50 to 200 μm and 60 to 1 μm.
It is composed of a 20-mesh net, and its base surface 7 is provided with a recess 8 for forming a black watermark in a desired pattern or character.

As the concave-shaped mesh roll 6 of a dandy roll used for making ordinary paper, a mesh having a filament diameter of 234 to 295 μm and a mesh of 40 to 60 mesh is usually used . In this embodiment, the wire diameter is 50 to 200 μm, 6
The reason why the mesh of 0 to 120 mesh is used is to sharpen the edges of the design or character formed by the recess 8. In this case, since the filament diameter is small, there is a concern that the filament may be cut when the concave portion 8 is formed by embossing with a press machine. In a female mold having a recess of 0.5 mm or more, the corners and corners of the mold are rounded to prevent filament breakage. Phosphor bronze is most suitable as the material of the filament having such a wire diameter, but stainless steel, polyester, polyamide or the like may be used.

Next, the concave portion 8 formed in the concave shaping net roll 6 will be described. As shown in FIG. 1, the recessed portion 8 is continuously or fragmented by a top regulating surface 9 acting on the stock web and defining the top surface of the black watermark, and a side regulating surface 10 defining the side surface of the black watermark. It is composed.

[0015] These ceiling regulation surface 9, side regulation surface 10,
Further the outer surface of the filament 11 constituting each around the base surface 7 of the recessed portion 8, 15% to 30%, for example sandpaper of diameter of the filament 11 as shown in FIG. 6
-P has been polished. Incidentally, this point is a characteristic configuration of the present invention, which enhances the smoothness of the ceiling regulating surface 9, the side regulating surface 10, and the base surface 7 around the concave portion, and also reduces the diameter of the filament 11, so that shaping is performed. The formed black watermark has the advantage that the edges of patterns and characters become clear. In addition, the method of polishing the filament 11 in this manner can be applied to a filament having a wire diameter of 234 μm to 295 μm which is applied to general papermaking.

If the filament 11 is polished, the strength is reduced. To compensate for this, plating with chrome having a high Vickers hardness can be performed. For example, in the case of a wire mesh using a phosphor bronze filament having a Vickers hardness of 130 to 200 Hv, bulging, scratching, and deformation of the concave portion are performed by plating with chrome (Vickers hardness 750 to 800 Hv) of 5 to 50 μm. Can be reduced.

Next, the appearance of the recess 8 will be described. First, the ceiling regulating surface 9 in the recess 8 is flat as shown in FIG. By the way, since the concave-shaped net roll 6 is formed by rolling a concave-shaped flat net having a concave portion formed by embossing with a mold in a cylindrical shape, the ceiling regulating surface 9 in the concave portion 8 becomes a convex curved surface. As usual, in the present embodiment, the top regulating surface 9 is made flat in the process of forming the concave portion 8. This point will be described in detail in a method of manufacturing a concave-shaped mesh roll described later.

Further, the side regulating surface 10 in the recess 8 is formed at an angle of 30 ° to 90 ° with respect to the base surface 7 as shown in FIG. It should be noted that such an angle is also meaningful in order to increase the contrast at the edges of the design or character of the black watermark.

Next, the relationship between the concave-shaped net roll 6 and the lower net roll 5 will be described. First, in the lower net roll 5, as shown in FIG. 2, a cutout portion 12 that is 10 to 20 mm larger than the concave portion 8 is formed corresponding to the concave portion 8 of the concave-shaped net roll 6. Then, when viewed from the back side of the concave portion 8 of the concave-shaped netting roll 6, that is, the concave portion 8, the convexly bulging portion is loosely fitted into the notch portion 12. I have.

By adopting a loose fitting structure of the recess 8 of the concave-shaped net roll 6 and the notch 12 of the lower net roll, even if the dandy roll 1 is used for a long time, the concave portion 8
Is not deformed and the step between the recess 8 and its surroundings is maintained, so that the sharpness of the black watermark can be ensured. Incidentally, such a structure is not inevitable in relation to the present invention, and even if the lower net exists at the position of the recessed portion 8, there is a problem in forming the black watermark in a short time. Not something.

The dandy roll 1 has the structure as described above. Hereinafter, a method of manufacturing the concave-shaped net roll 6 will be described focusing on a method of forming the concave portion 8. First, before starting the description of the method of manufacturing the concave-shaped netting roll 6, a mold for forming the concave portion 8 will be described. This metal mold is formed by forming irregularities on the surface of a metal plate by, for example, etching or an NC router, and can take a form of either the male mold 13 or the female mold 14 or a form having both of them.

In the male mold 13, as shown in FIG. 5 (a), a slightly raised convex working surface 13 b is formed on the convex portion 13 a for shaping the wire net into a desired shape, while in the female mold 14, As shown in FIG. 5 (b), a slightly concave working surface 14b is formed in the concave portion 14a for shaping the wire net into a desired shape. The rise and fall of the working surface 13b of the male mold 13 and the depression of the working surface 14b of the female mold 14 are:
It is directly related to the shape of the recessed portion 8 in the intaglio-shaped net roll 6, and is also related to the sharpness of the black watermark.

Here, taking the male mold 13 as an example, the rise and fall of the working surface 13b in the male mold 13 will be described. When the working surface 13b of the male mold 13 is slightly raised, the depression 8
In FIG. 5A, the top regulating surface 9 in the shape of the top is slightly concavely adjusted, that is, a shape in which a concave curve is drawn, and this is wound in a roll shape so that the concave portion 8 is on the outside. In addition, the depression of the ceiling regulating surface 9 is deformed so as to approach a plane. Therefore, the swelling of the working surface 13b of the male mold 13 is adjusted when the flat mesh formed with the recessed portion 8 is wound around the lower mesh by embossing with the male mold 13.
Are set to be substantially flat by deformation. By the way, since the top regulating surface 9 of the recess 8 becomes substantially flat in a state of being wound on the lower net, the stock web can be present in the recess 8 with a substantially uniform thickness. Can be prevented.

The rise and fall of the working surface 13b of the male mold 13 depends on the width of the recess 8 and the diameter of the dandy roll 1 (= the diameter of the concave-shaped net roll 6). Although it is generally difficult to express by numerical values or the like, as one guide for defining the swelling state of the working surface 13b, as shown in FIG. 4, the radius of the concave-shaped net roll 6 is r, and the depth of the concave portion 8 is a. And the working surface 13
What is necessary is just to make the cross section of b bulge so that the cross section substantially follows the curve represented by x ² + y ² = (r−a) ² . still,
The same applies to the determination of the recessed state of the working surface 14b in the female mold 14.

As described above, the corners 15 and 16 of the mold are slightly rounded so that the net is not cut during embossing when a thin filament is employed. ing.

The above is the schematic structure of the mold, performing the embossing work with such a mold. That is, first, as shown in FIG. 6, a flat screen 18 is prepared, desired characters and patterns to be black-marked are drawn on the flat screen 18, and the portion is formed using a # 400 sandpaper P with a diameter of 15 to 15 mm.
Polish 30%. The polishing is a feature of the present invention, the purpose of which is as described above, and the polishing method is not particularly limited.

Next, the flat mesh 18 is placed on the rubber sheet G, and the male mold 13 or the female mold 14 is set thereon so that the polished portion of the flat mesh 18 coincides with the working surface 13b or 14b of the mold. I do. Then, in this state, the mold is pressed by using a press machine or the like, so that the recess 8 is formed in the flat net 18. In addition, the flat screen 18 in which the recessed portion 8 is formed is defined as a concave shaped flat screen 19. By the way, in such a state of the concave-shaped flat screen 19, the top regulating surface 9 in the concave portion 8 is, as shown in FIG.
Alternatively, the working surface 13b or 14b of the female mold 14 is raised or recessed by the amount of the recess.

[0028] The flat net 19 having such a concave shape is formed by the lower net roll 5.
The lower net roll 5 is formed with a notch 12 at a position corresponding to the recess 8 of the concave-shaped flat screen 19 in advance.
2, the concave-shaped net 19 is wound while the convex portion on the back side of the concave portion 8 is fitted.
State. As a result, the ceiling regulating surface 9 in the recess 8
Is corrected to a substantially planar state. Note that the notch 12 may be formed after the concave-shaped net roll 6 is in the state.

Next, the formation of a black watermark using the dandy roll 1 to which such a concave-shaped mesh roll 6 is applied will be described. Such a dandy roll 1 may be handled in the same manner as a normal watermark forming operation. As shown in FIG. 1, the base surface 7 of the dandy roll 1 faces the stock web A at a constant pressure. The recess 8 is made to act on the stock web A while rotating 1. The rotation of the dandy roll 1 can be driven by a separate drive unit in accordance with the wire speed, in addition to the natural drive by friction with the wire.

As a result, part of the stock web A where the base surface 7 of the dandy roll 1 has acted escapes into the recess 8, and the web thickness and density of the recess 8 become higher than those of the other portions. . By drying in this state, a black watermark is formed. Here, in order to form a clear black watermark, the change in basis weight between the black watermark portion and the other portions is 10 to 7%.
It is preferably 0 g / m ² . Further, since the ceiling regulating surface 9 in the concave portion 8 can be made substantially flat, a black watermark having no continuous gradation expression of 0.25 to 25 cm ² can be performed.

[0031]

In order to confirm the effect of the present invention, an example of the present invention was compared with a comparative example. <Example 1> The surface of a 65-mesh net made of phosphor bronze was polished to 15% of the filament diameter with sandpaper (# 400), and a rubber sheet and a stainless steel having a convex portion having a height of 0.8 mm by etching were used. It was placed between molds, and was pressed by a press at a pressure of 20 kg / cm ² . This net was attached as a concave-shaped net roll of a dandy roll, and papermaking was performed to a weight of 65 g / m ² using a stock web having 100 parts of LBKP and a freeness of 65 ° SR.

Example 2 The surface of a phosphor bronze 65-mesh plain weave net was polished with sandpaper (# 400) to 25% of the filament diameter, and chromium plating was performed until the plating thickness became 15 μm. This net was placed between a rubber sheet and a stainless steel mold having a convex portion having a height of 0.8 mm by etching, and was pressed at 20 kg / cm using a press machine.
^The mold was pressed at a pressure of ² . This net is mounted as a dandy roll concave shaped net roll, and the LBKP100
Part, 65 g using a stock web with a freeness of 65 ° SR
/ M ² .

COMPARATIVE EXAMPLE 1 A 65-mesh net made of phosphor bronze was woven with a rubber sheet and etched to a height of 0.8 m.
The mold was placed between stainless steel molds having m convex portions, and the mold was pressed at a pressure of 20 kg / cm ² using a press machine.
This net was attached as a concave-shaped net roll of a dandy roll, and papermaking was performed so as to be 65 g / m ² using a stock web having 100 parts of LBKP and a freeness of 65 ° SR. Table 1 shows the results of Examples 1 and 2 and Comparative Example 1.

[0034]

[Table 1] Example 1 Example 2 Comparative Example 1-Surface polishing (%) * 15250-Chrome plating thickness (μm) 0 150-Sharpness of black watermark ○ ○ × ・ Basis weight per 1 mm length 24 20 6.9 Variation (g / m ² ) * Polishing depth when filament diameter was 100 was expressed as a percentage.

As shown in Table 1, according to the present invention, paper having a clear black watermark pattern can be provided.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a use state of a black watermark dandy roll of the present invention.

FIG. 2 is a cross-sectional view showing, on an enlarged scale, an upper side view of the same and an arrow section of the same.

FIG. 3 is an explanatory diagram showing a range of a forming angle of a side regulating surface in a concave portion.

FIG. 4 is an explanatory diagram showing, by symbols, a radius dimension of a concave-shaped net roll and a depth dimension of a concave portion.

FIG. 5 is an explanatory view showing a state in which a concave portion is formed by a male mold and a female mold, and when the concave portion is wound into a roll, the ceiling regulating surface becomes flat.

FIG. 6 is an enlarged cross-sectional view showing a state where a portion of a flat net to be black-marked is polished with sandpaper.

FIG. 7 is a cross-sectional view showing a state where the polished flat net is set on a rubber sheet.

FIG. 8 is a cross-sectional view showing a state in which a recess is formed in the flat mesh.

FIG. 9 is a cross-sectional view showing a state in which the concave-shaped flat net is wound in a roll shape on a lower net roll having a cutout portion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Dandy roll 2 Roll main body 3 Center axis 4 Disk 5 Lower net roll 6 Concave shaped net roll 7 Base surface 8 Depression 9 Top regulation surface 10 Side regulation surface 11 Filament 12 Notch 13 Male 13a Convex portion 13b Action Surface 14 Female mold 14a Depressed portion 14b Working surface 15 Corner ridge 16 Corner corner 18 Flat net 19 Concave shaped flat net A Paper web G Rubber sheet P Sandpaper

Claims (3)

(57) [Claims] 1. A dandy roll having a surface formed by a concave-shaped net roll formed with a concave portion for forming a black watermark, wherein the concave portion and an outer surface around the concave portion have a concave-shaped net. A dandy roll for black watermark, which is polished by 15 to 30% of the diameter of a filament constituting the roll. 2. The dandy roll for black watermark according to claim 1, wherein the dandy roll is chrome-plated. 3. A flat net is formed by press-forming a flat net using a mold to form a concave-shaped flat net having a concave portion for black watermark forming. The flat net is wound around a lower net roll to form a dandy. In the method for producing a roll, before press forming the flat mesh,
A method for manufacturing a dandy roll for black watermarking, wherein a recess forming position in a flat net is polished in advance by 15 to 30% of a diameter of a filament constituting the flat net.