JPH06123093A - Dandy roll for black openwork and its production - Google Patents

Abstract

PURPOSE:To provide the subject roll capable of giving the edges of patterns or letters a clear black openwork by abrading a recess for black openwork formation and the outer face of the recess at specified levels relatively to the diameter of the filaments of a recess-shaped net roll to improve the smoothness of the recess face. CONSTITUTION:A flat net 18 is press-molded using a mold 13 to make a recess- shaped flat net 19 formed with a recess 8 for black openwork formation, and this net 19 is wrapped on a lower net roll 5 to make a dandy roll. In this case, prior to the press molding, the recess forming site on the net 18 is abraded using, e.g. sand paper P to such an extent as to be 15-30% of the diameter of the filaments 11 making up the net 18 to improve the smoothness of the respective faces of the recess and give paper a clearness in the edge parts of black openwork pattern or letters because the filaments 11 get thin, thus obtaining the objective dandy roll having such advantages.

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 to provide a watermark pattern when making paper, and a method for producing the same.

[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, the net of dandy roll for producing general paper has a wire diameter of 234 to 295 μm, 40 to 6
Although 0 mesh is used, in the case of such a mesh, the edges of the design and characters are not clear.

Therefore, as a device for making the edge portion of the design or character clear, a method of increasing the number of meshes of the mesh to reduce the distance between the filaments or thinning the filaments of the mesh can be considered. However, the former method has a problem in that dandy rolls are contaminated, and the latter method has a problem in that the net is likely to be swollen, damaged, or deformed.

[0006]

[Technical Items Attempted to Develop] The present invention has been made in view of such a background, and the present inventor, when forming a black watermark, sharpens the pattern of the black watermark and the edge portion of the character. This is an attempt to develop a new dandy roll for black watermark and a manufacturing method thereof.

[0007]

[Constitution of the invention]

[Means for Achieving the Object] That is, the first invention of the present application, a dandy roll for black watermark, is a dandy roll whose surface is constituted by a concave shaped net roll in which a concave portion for forming a black watermark is formed. In the above, the concave portion and the outer surface around the concave portion are formed by polishing 15 to 30% of the diameter of the filament forming the concave shaped net roll.

In addition to the above requirements, the second watermarking dandy roll according to the present invention is characterized in that the dandy roll is chrome-plated.

Further, a third invention of the present invention, which is a method for manufacturing a dandy roll for black watermark, is a concave-shaped flat mesh in which a flat mesh is press-molded by using a mold to form a concave portion for black watermark molding. In the method for producing a dandy roll by winding this concave shaped flat net around the lower net roll, before press forming the flat net, the concave portion forming position in the flat net is a filament forming the flat net. 15 of the diameter of
It is characterized by polishing by 30%. The above objects are achieved by these inventions.

[0010]

According to the present invention, the concave portion of the concave shaped net roll of the dandy roll and the outer surface forming the periphery thereof are polished by 15 to 30% of the diameter of the filament forming the concave shaped net roll. Therefore, the smoothness of each surface forming the recess is improved and the filament diameter is reduced. Therefore, in the black watermark produced by using such a concave shaped net roll, the edge portion of the design or character becomes clear.

[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 net roll 6 of the dandy roll used in the papermaking of general paper, a net having a filament diameter of 234 to 295 μm and 40 to 60 mesh is usually used. At a wire diameter of 50 to 200 μm,
The reason why the mesh of 60 to 120 mesh is applied is that the concave portion 8
This is for sharpening the edges of the design and characters formed by. In this case, since the filament wire diameter is small,
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 having a height of 0.5 mm or more or a female mold having a concave portion having a depth of 0.5 mm or more. Then, the roundness is imparted to the corners and corners of the mold to prevent the filament from breaking. 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,
Furthermore, as shown in FIG. 6, 15 to 30% of the diameter of the filament 11 is polished on the outer surface of the filament 11 which constitutes the base surface 7 around the recess 8. By the way, this point is a characteristic configuration of the present invention. As a result, the smoothness of the ceiling control surface 9, the side control surface 10 and the base surface 7 around the recessed portion is increased, and the diameter of the filament 11 is reduced, so It is easy to remove, and the formed black watermark has the advantage that the edges of patterns and characters become clear. The method of polishing the filament 11 in this way can also be applied to a filament having a wire diameter of 234 μm to 295 μm 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 it is possible to adopt either a male mold 13 or a female mold 14 or a form including both.

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. It should be noted that 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
It is directly related to the shape of the concave portion 8 in the concave shaped net roll 6 and, in turn, related to the definition 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 numerical values etc., 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 dimension of the concave portion 8 is a. Then, the working surface 13
The transverse section of b may be in a raised state so as to substantially follow 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 of the female die 14.

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 screen 18 is prepared, and desired characters and designs for black watermarking are drawn on the flat screen 18, and the part is # 40.
Sandpaper P of 0 is used to grind 15 to 30% of the diameter of the filament. It should be noted that such 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 net 18 is placed on the rubber sheet G, and the male mold 13 or the female mold 14 is placed on the rubber net G so that the polished portion of the flat net 18 is aligned with the working surface 13b or 14b of the mold. To do. 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. The flat net 18 in which the concave portion 8 is formed is defined as a concave shaped flat net 19. By the way, in such a state of the concave shaped flat net 19, the ceiling control 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 depressed by the height or depression.

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. The cutout portion 12 may be formed after the concave shaped net roll 6 is brought into the state.

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, 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.

[0031]

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

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

Comparative Example 1 A 65-mesh plain weave net made of phosphor bronze is 0.8 m in height by etching with a rubber sheet.
It was placed between a stainless steel mold having a convex portion of m and pressed using a press machine at a pressure of 20 kg / cm ² .
This net was attached as a concave shaped net roll of a dandy roll, and paper was made to a weight of 65 g / m ² using a stock web having 100 parts LBKP and a freeness of 65 ° SR. 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-Surface polishing (%) * 15250-Chrome plating thickness (μm) 0150-Clearness of black watermark ○ ○ × -Basis weight per 1 mm in length 24 20 6.9 Change (g / m ² ) * The polishing depth is expressed as a percentage when the filament diameter is 100.

As shown in Table 1, the present invention can provide a paper having a clear black watermark pattern.

[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 the polished flat mesh 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.

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

Claims (3)

[Claims] 1. A dandy roll whose surface is constituted by a concave shaped net roll having a concave portion for forming a black watermark, wherein the concave portion and an outer surface around the concave portion are concave shaped nets. A dandy roll for black watermark, which is obtained by polishing 15 to 30% of the diameter of filaments constituting the roll. 2. The dandy roll for black watermark according to claim 1, wherein the dandy roll is chrome-plated. 3. A flat mesh is press-molded using a mold to form a concave shaped flat net in which a concave portion for black watermark molding is formed, and the concave shaped flat net is wound around a lower net roll to make a dandy. In the method for producing a roll, before press-forming the flat screen,
A method for producing a dandy roll for black watermarking, characterized in that the recessed portion forming position in the flat net is previously polished by 15 to 30% of the diameter of filaments constituting the flat net.