JPH06123091A - Production of recess shaping net roll for dandy roll and mold therefor - Google Patents

Abstract

PURPOSE:To provide the subject roll by pressing a flat net and forming the top limiting face of a recess in a recess-shaped flat net mode and then rolling the flat net to give paper stock web uniform in thickness in the recess a black openwork free from gradation. CONSTITUTION:A flat net 18 is pressed to form a recess-shaped flat net 19 with a recess 8 for openwork formation, and this flat net 19 is then rolled to produce a recess-shaped net roll 6. In this case, using a mold wherein the respective action faces 13b, 14b of male force 13 or female force 14 to be used for pressing the flat net 18 is provided in a protuberance or recessed manner virtually according to a curve given by the formula ((r) is radius of the recess- shaped net roll; (a) is depth of the recess), the top limiting face 9 in the recess 8 is formed in a recessed manner in a recess-shaped flat net mode, and the net 19 is rolled almost flat, thus obtaining the objective roll capable of giving paper stack web uniform in thickness in the recess 8 with black openwork free from gradation.

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 method for producing a concave shaped net roll for a dandy roll used to provide a watermark pattern when paper is made, and a mold used for the method.

[0002]

BACKGROUND OF THE INVENTION Watermark patterns provided on paper include black watermarks and white watermarks. In black watermarks, the watermark pattern portion appears darker than the surroundings, while in white watermark, the watermark pattern portion is visible. It is a thing. In both cases, the thickness or density of the stock web is changed in the papermaking stage to develop a watermark pattern.

Several methods have already been developed for such a method, but in the wire part during the papermaking process, an apparatus provided with a water-permeable holding net called a dandy roll on the roll surface is a paper stock. A method has been considered in which a basis weight change such as a thickness change or a density change is given to a part of the stock web by the unevenness having a shape corresponding to the pattern provided on the surface of the dandy roll, which acts on the web. The points that require technical measures for forming such a watermark are that the watermark is clearly expressed and that the watermark can be stably processed during papermaking.

By the way, in order to put a black watermark of a design or a character on the paper due to the unevenness of the surface of the dandy roll, a flat mesh is pressed by a mold to form a concave portion to form a concave shaped flat mesh. Use the one wrapped around a roll. However, when a black watermark is put in an area of 5 mm × 5 mm or more, when the concave shaped flat net 19 'is attached to the dandy roll 1'as shown in FIG. 10, the concave shaped flat net 19' becomes a roll shape. Since it is bent, the ceiling control surface 9'in the concave portion 8'becomes a curved surface. Therefore, when the recessed portion 8 ′ acts on the stock web, as shown in FIG. 10, the vicinity of the center of the embossed portion becomes thin, and the vicinity of both ends becomes thick. As a result, when observing the black watermark portion with transmitted light, 5 mm x 5 m
Differences in the amount of light transmission occur within an area of m or more, resulting in gradation expression.

[0005]

[Technical Items Attempted to Develop] The present invention has been made in view of such a background, and the present inventor made a dandy in which a gradation expression of a black watermark is prevented when forming a black watermark. An attempt was made to develop a method for producing a concave shaped net roll for a roll and a die used for the method.

[0006]

[Constitution of the invention]

[Means for Achieving the Object] That is, the first invention of the present application is a method for producing a dented roll-shaped mesh roll for dandy rolls, wherein a flat mesh is pressed to form a concave portion for forming a black watermark. In the method of forming a shaped flat net and winding the concave shaped flat net in a roll shape to manufacture a concave shaped net roll, the ceiling control surface in the concave portion is formed in a dent shape in the concave shaped flat net state. The concave shaped flat net is formed into a substantially flat surface by winding it in a roll shape.

In addition to the above-mentioned requirements, the second aspect of the present invention, which is a method for producing a concave-shaped mesh roll for dandy rolls, is such that the ceiling control surface in the concave portion is x ² + y ² = (r−a) ² (r is the radial dimension of the concave shaping net roll, and a is the depth dimension of the concave portion) is formed in a dent shape substantially according to a curve. .

Further, the metal mold used in the manufacture of the concave-shaped netting roll for dandy rolls according to the third invention of the present application is a concave-shaped metal mold formed by pressing a flat mesh to form a concave portion for black watermark molding. In a male mold used to press a flat net when forming a flat net and winding the flat net to form a concave net roll, the working surface of the male mold is x ² + y ² = (R−a) ² (r is the radial dimension of the concave shaped net roll, and a is the depth dimension of the concave portion) is formed in a bulge shape almost according to a curve. .

Furthermore, the mold used in the manufacture of the concave shaped net roll for dandy rolls according to the fourth invention of the present application is a concave formed by pressing a flat mesh to form a concave portion for black watermark molding. In a female die used for pressing a flat net when forming a shaped flat net and winding the concave flat net in a roll shape to produce a concave flat net roll, the working surface of the female die is x ² + y ² = (r−a) ² (r is the radial dimension of the concave shaping net roll, and a is the depth dimension of the concave portion), and is characterized by being formed in a dent shape substantially according to the curve. is there. The above objects are achieved by these inventions.

[0010]

According to the present invention, the ceiling control surface in the recessed portion is formed in a dent shape in the concave shaped flat-mesh state, and is formed into a substantially flat surface by winding the concave shaped flat net in a roll shape. When a concave shaped flat mesh is attached around a dandy roll to form a concave shaped net roll, the ceiling control surface in the concave portion becomes a flat surface, the thickness of the stock web becomes uniform in the concave portion, and the gradation A black watermark without expression can be created.

[0011]

The present invention will be described below with reference to the illustrated embodiments. Reference numeral 1 is a dandy roll to which the present invention is applied. As shown in FIG. 1, the dandy roll has, as an example, a central shaft 3 passed through the axial center of a roll main body 2, and the central shaft 3 is a disc at regular intervals. 4 is provided to form a body, and a structure for supporting the roll main body 2 is adopted. The roll main body 2 comprises a lower net roll 5 directly provided on the disc 4 and a concave shaped net roll 6 provided on the lower net roll 5.

The concave shaped net roll 6 is for acting on the stock web to form a black watermark, which has a filament wire diameter of, for example, 50 to 200 μm and 60 to 1
A 20-mesh net is formed, and a concave portion 8 for forming a black watermark is formed on the base surface 7 in a desired pattern or character.

As the concave shaped mesh roll 6 of the dandy roll used in the papermaking of general paper, a mesh having a filament diameter of 234 to 295 μm and 40 to 60 mesh is usually used. Wire diameter 50-200 μm, 6
The reason why the mesh of 0 to 120 mesh is applied is to make the edge portion of the pattern or character formed by the concave portion 8 clear. In this case, since the filament has a small wire diameter, there is a concern that the filament may be cut when the concave portion 8 is formed by pressing with a press machine, but a male mold having a convex portion with a height of 0.5 mm or more or a depth of 0 mm. In a female mold having a recess of 0.5 mm or more, the breakage of the filament can be prevented by giving roundness to the corner ridges and corners of the mold. Although phosphor bronze is most suitable as the material of the filament having such a wire diameter, 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 that acts on the stock web to define the top surface of the black watermark and a side regulating surface 10 that defines the side surface of the black watermark. Is composed of

These ceiling control surface 9, side control surface 10,
Further, the outer surface of the filament 11 forming the base surface 7 around the recessed portion 8 may be polished by 15 to 30% of the diameter of the filament 11 as shown in FIG. By the way, in the case of polishing, the top regulation surface 9 and the side regulation surface 1
0 and the smoothness of the base surface 7 around the recessed portion increases,
Since the diameter of the filament 11 becomes thin, it is easy to shape, and the formed black watermark has an advantage that the edge portion of the design or character becomes clear. The method of polishing the filament 11 in this way can also be applied to a filament having a wire diameter of 234 to 295 μm which is applied to papermaking of general paper.

Further, when the filament 11 is polished, its strength is lowered. To compensate for this, it is possible to plate with chrome having a high Vickers hardness. For example, in the case of a wire mesh using a phosphor bronze filament having a Vickers hardness of 130 to 200 Hv, plating with 5 to 50 μm of chrome (Vickers hardness of 750 to 800 Hv) causes swelling, scratches, and deformation of the recessed portion. Can be reduced.

Next, the appearance of the recess 8 will be described. First, the ceiling control surface 9 in the recess 8 is flat as shown in FIG. By the way, the concave shaping net roll 6 is formed by rolling a cylindrical shaped flat net having a concave portion formed by pressing with a metal mold, so that the ceiling control surface 9 in the concave portion 8 is a convex curved surface. As usual, in the present embodiment, the ceiling regulating surface 9 is devised in the process of forming the recessed portion 8. This point will be described in detail in the method of manufacturing a concave shaped net roll described later.

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 significant in order to enhance the contrast at the black watermark pattern and the edge portion of the character.

Next, the relationship between the concave shaping 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 notch 12 having a size 10 to 20 mm larger than the concave 8 is formed corresponding to the concave 8 of the concave shaped net roll 6. Then, the back surface of the recessed portion 8 of the recessed netting roll 6, that is, the portion that is convexly bulged when the recessed portion 8 is viewed from the back side is gently fitted into the cutout portion 12. There is.

Incidentally, by adopting the loose fitting structure of the recessed portion 8 of the concave shaping net roll 6 and the cutout portion 12 of the lower netting roll in this manner, the recessed portion 8 is used even if the dandy roll 1 is used for a long time.
Since there is no deformation and the step between the concave portion 8 and its surroundings is maintained, the sharpness of the black watermark can be secured. It should be noted that such a structure is not inevitable in relation to the present invention, and even if the lower net is present at the position of the recessed portion 8, it will hinder the formation of the black watermark in a short time. Not a thing.

The dandy roll 1 has the structure as described above, and the method of manufacturing the concave shaped net roll 6 will be described below centering on the method of forming the concave portion 8. First, before entering the description of the method for manufacturing the concave shaped net roll 6, a mold for forming the concave portion 8 will be described. This mold is one in which concavities and convexities are formed on the surface of a metal plate by etching or an NC router, for example, and can take either form of the male mold 13 or the female mold 14 or both forms.

In the male die 13, as shown in FIG. 5 (a), a slightly raised working surface 13b is formed on the convex portion 13a for shaping the wire mesh into a desired shape, while in the female die 14, As shown in FIG. 5 (b), a slightly depressed action surface 14b is formed in the recessed portion 14a for shaping the wire mesh into a desired shape. Note that such a configuration is a characteristic configuration of the present invention, and the swelling of the working surface 13b of the male mold 13 and the swelling of the working surface 14b of the female mold 14 are defined as the concave recesses in the concave shaping net roll 6. Directly related to the form of part 8,
As a result, it is also related to the sharpness of the black watermark.

Here, taking the male die 13 as an example, the rise and fall of the working surface 13b of the male die 13 will be described. By making the working surface 13b of the male die 13 slightly raised, when the flat net is impressed by the male die 13, the concave portion 8 is formed.
The ceiling control surface 9 in FIG. 6 has a shape with a slight depression, that is, a shape that draws a concave curve, but by winding this in a roll shape so that the concave portion 8 is on the outside, as shown in the lower part of FIG. In addition, the degree of depression of the ceiling control surface 9 deforms so as to approach a flat surface. Therefore, the rise and fall of the working surface 13b of the male die 13 is adjusted when the flat net formed with the male die 13 and having the recessed portion 8 is wound around the lower net.
Is set so that it becomes almost flat due to deformation. By the way, since the ceiling control surface 9 of the concave portion 8 becomes substantially flat in a state of being wound on the lower net, the stock web can be present in the concave portion 8 with a substantially uniform thickness. The gradation expression of can be prevented.

The rise and fall of the working surface 13b of the male die 13 depends on the width dimension of the concave portion 8 and the diameter dimension of the dandy roll 1 (= the diameter dimension of the concave shaping net roll 6). Although it is generally difficult to express numerically, in the present invention, as one guideline for defining the rising state of the working surface 13b, as shown in FIG. 4, the radius dimension of the concave shaping net roll 6 is r, and the depth of the concave portion 8 is When the dimension is a, the cross section of the working surface 13b is formed in a swelling state so as to substantially follow the curve represented by x ² + y ² = (r−a) ² . The above is the working surface 14b of the female mold 14.
The same applies to the determination of the depression state of.

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

The above is the schematic structure of the die 15, and the die 15 is used to perform the die pressing operation. That is, first, as shown in FIG. 6, a flat net 18 is prepared, placed on a rubber sheet G, and the male mold 13 or the female mold 14 is placed thereon and set. Then, in this state, the mold is pressed by using a pressing machine or the like to form the concave portion 8 in the flat net 18. In addition, the concave portion 8
The flat net 18 on which is formed is defined as a concave shaped flat net 19. By the way, in the state of such a concave shaped flat net 19, the ceiling control surface 9 in the concave portion 8 is only the amount of swelling or depression of the action surface 13b or 14b in the male mold 13 or the female mold 14 as shown in FIG. It becomes depressed.

Such a concave shaped flat net 19 is used for the lower net roll 5
The lower net roll 5 has a notch 12 formed in advance at a position corresponding to the concave portion 8 of the concave shaped flat net 19, and the notch 1 is formed on the lower net roll 5 in advance.
With respect to 2, the concave shaped flat net 19 is wound while the convex portion on the back side of the concave portion 8 is fitted, and the concave shaped net roll 6
To the state of. As a result, the ceiling control surface 9 in the concave portion 8
The dented state of is corrected so that it becomes almost flat.

Next, the formation of a black watermark using the dandy roll 1 to which the concave shaping net roll 6 is applied will be described. Such a dandy roll 1 may be handled in the same manner as a normal watermark forming work, and as shown in FIG. 1, the base surface 7 of the dandy roll 1 is faced with a constant pressure against the stock web A so that the dandy roll 1 is exposed. The concave portion 8 acts on the stock web A while rotating 1. The rotation of the dandy roll 1 may be driven naturally by friction with the wire, or may be driven by a separate driving device so as to match the wire speed.

As a result, a part of the stock web A on which the base surface 7 of the dandy roll 1 has acted escapes into the concave portion 8 and the web thickness and density of the concave portion 8 become higher than the other portions. . By drying in this state, a black watermark is formed. Here, in order to form a clear black watermark, the amount of change in basis weight between the black watermark portion and other portions is 10 to 7
It is preferably 0 g / m ² . Further, since the ceiling control surface 9 in the concave portion 8 can be made substantially flat, a black watermark of 0.25 to 25 cm ² without continuous gradation expression can be performed.

[0030]

In order to confirm the effects of the present invention, the examples of the present invention and comparative examples were compared. The diameter of the dandy roll applied to each example is 305 mm, and the depth of the recess is 0.5 mm.

<Example 1> The surface of a metal plate was x ² + y ²
= 23104 (unit: mm) was convexly polished, a photosensitive resin was applied, and then exposed and washed to obtain a stainless steel mold having a convexity of 0.8 mm in height by etching. The value of 23104 is [(305
/2)-0.5] ² . Next, a 65-mesh plain weave net made of phosphor bronze was placed between the rubber sheet and the mold, and embossed by a pressure of 30 kg / cm ² to prepare a concave shaped flat net. This concave shaped flat mesh has a diameter of 3
It was attached to a 05 mm dandy roll as a concave shaped net roll, and paper was made at 65 g / m ² using a stock web having 100 parts LBKP and a freeness of 55 ° SR.

<Embodiment 2> The surface of a metal plate is x ² + y ²
= 23104 (unit: mm), polished into a concave shape, coated with a photosensitive resin, exposed to light, washed, and then etched to obtain a stainless steel metal having a concave portion having a depth of 0.8 mm and an area of 5 mm × 5 mm. A mold was made. Next, a 65-mesh plain weave net made of phosphor bronze was placed between the rubber sheet and the mold, and embossed with a pressure of 30 kg / cm ² to form a concave shaped flat net. This concave shaped flat net is attached to a 305 mm diameter dandy roll as a concave shaped net roll, and LB
A paper stock having a KP of 100 parts and a freeness of 55 ° SR was used to make 65 g / m ² .

Comparative Example 1 A stainless steel plate having a flat surface was coated with a photosensitive resin, which was then exposed to light and washed,
0.8mm height and 5mm x 5mm area by etching
A mold having a convex portion of was produced. A 65-mesh plain weave net made of phosphor bronze was placed between the rubber sheet and the mold, and embossed with a press machine at a pressure of 30 kg / cm ² to prepare a concave shaped flat net. This concave shaped flat net is attached as a concave shaped net roll to a dandy roll with a diameter of 305 mm, and LBKP
A paper stock having 100 parts and a freeness of 55 ° SR was used to make paper at 65 g / m ² . The results of Examples 1 and 2 and Comparative Example 1 are shown in Table 1.

[0034]

Table 1 Example 1 Example 2 Comparative Example 1 Type of curved treatment Yes Yes No symbol size 10mm × 10mm 5mm × 5mm 5mm × 5mm symbol in the basis weight difference there None None gradation (g / m ²⁾ 6 8 16

As shown in Table 1, according to the present invention, a paper having a black watermark pattern without gradation expression can be provided.

[Brief description of drawings]

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

FIG. 2 is a cross-sectional view showing a side view of the same as above and an enlarged view of an arrow portion in the same figure.

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

FIG. 4 is an explanatory diagram showing the radius dimension of the concave shaping net roll and the depth dimension of the concave portion with symbols.

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

FIG. 6 is an enlarged cross-sectional view showing a state in which a black watermarked portion of a flat net is polished with sandpaper.

FIG. 7 is a cross-sectional view showing a state in which a flat net is set on a rubber sheet.

FIG. 8 is a cross-sectional view showing how a concave portion is formed in the flat screen.

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 formed therein.

FIG. 10 is a cross-sectional view showing a state in which a black watermark is expressed in a gradation manner by forming a curved ceiling control surface in a recess.

[Explanation of symbols]

 1 dandy roll 2 roll body 3 central axis 4 disc 5 lower net roll 6 concave shaped net roll 7 base surface 8 recessed portion 9 top regulating surface 10 side regulating surface 11 filament 12 notch portion 13 male type 13a convex portion 13b action Surface 14 Female 14a Recessed portion 14b Working surface 15 Corner ridge 16 Corner corner 18 Flat mesh 19 Recessed shaped flat mesh A Paper stock web G Rubber sheet P Sandpaper

Claims (4)

[Claims] Claim: What is claimed is: 1. A flat-shaped net is pressed to form a concave-shaped flat net formed by forming a concave portion for forming a black watermark, and the concave-shaped flat net is wound in a roll shape to form a concave-shaped flat net roll. In the method for producing, the top regulating surface in the concave portion is formed into a dent shape in the concave shaped flat net state, and the concave shaped flat net is formed into a substantially flat surface by winding in a roll shape. A method for producing a concave shaped net roll for dandy rolls. 2. The ceiling control surface of the recessed portion is defined as x ² + y ² = (r−a) ² (r is the radial dimension of the recessed shaped mesh roll, and a is the depth of the recessed portion in the recessed shaped flat mesh state. 2. The method for producing a concave shaped net roll for dandy rolls according to claim 1, wherein the curved shape is represented by a curve, and the groove is formed substantially according to the curve. 3. A flat-shaped mesh is formed by pressing a flat mesh to form a concave portion for forming a black watermark, and the flat-shaped mesh is rolled into a roll shape to form a concave-shaped mesh roll. In the male die used for the press of the flat net in the production of the above, the working surface of the male die is x ² + y ² = (r−a) ² (r is the radial dimension of the concave shaped net roll, and a is the concave portion A mold for producing a concave shaped net roll for a dandy roll, which is formed in a swelling shape almost according to a curve represented by a depth dimension). 4. A flat-shaped mesh is formed by pressing a flat mesh to form a concave portion for forming a black watermark, and the flat-shaped mesh is rolled into a roll shape to form a concave-shaped mesh roll. In the female die used for the press of the flat net in the production of, the working surface of the female die is x ² + y ² = (r−a) ² (r is the radial dimension of the concave shaped net roll, and a is the concave portion. A mold for producing a concave shaped net roll for a dandy roll, which is formed in a dent shape substantially according to a curve represented by a depth dimension).