EP2899313A1 - Dewatering fabric for the production of watermarked paper - Google Patents

Abstract

The invention relates to a dewatering screen (40) for the production of paper with a watermark, in which the watermark to be produced in papermaking contains as motif component at least one gray progression line (14, 16) with a width of less than 1.0 mm running along their length or width has a stepless gray gradient. The dewatering screen (40) has a carrier screen with a screen surface (52) on which paper is deposited, and a perforated plastic watermark insert (60) arranged in a subregion of the carrier screen (42). The plastic watermark insert (60) contains at least one line-shaped motif element (62, 72) with a width of less than 1.0 mm, which has a stepless rise region along its length or width, in order to produce the gray gradient line (s) (14, 16) in that the distance to the sieve surface increases steplessly from a first distance value (a 1) to a second, larger distance value (a 2).

Description

The invention relates to a dewatering screen for the production of paper with a watermark and a method for producing such a dewatering screen.

In papermaking on round screening or screening machines, pulp accumulates continuously on a moving dewatering screen and is solidified to the extent that it can be removed as a wet paper web for further processing of the dewatering screen. Above all, security papers for banknotes, identity documents and the like are often provided with watermarks for securing purposes, which permit checking the authenticity of the security paper and which at the same time serve as protection against unauthorized reproduction.

Watermark paper can be equipped with two-level watermarks with a strong light-dark effect as well as with multi-level watermarks with smooth transitions between light and dark and detailed representation of a subject. For the production of multi-level watermarks, for example, a desired three-dimensional relief is embossed in a metal drainage screen. The paper thickness of the finished paper then varies according to the embossed relief and allows the transmission of soft, gradual transitions between lighter and darker areas.

From the publication WO 2008/071325 A1 For this purpose, the use of an injection-molded watermark insert is known, which forms a multi-level relief in the form of the watermark to be generated. Proceeding from this, the object of the invention is to provide a dewatering screen for the production of paper with a watermark, which combines an attractive visual appearance with high security against counterfeiting.

This object is solved by the features of the independent claims. Further developments of the invention are the subject of the dependent claims.

The invention comprises a dewatering screen of the type mentioned, in which the watermark to be produced in papermaking contains as motif component at least one gray-line with a width of less than 1.0 mm, which has a stepless gray course along its length or width. The dewatering screen has a carrier screen, with a screen surface on which paper is deposited, and a perforated plastic watermark insert arranged in a partial region of the carrier screen. The plastic watermark insert contains at least one line-shaped motif element with a width of less than 1.0 mm, which has a stepless rise region along its length or width, in which the distance to the sieve surface varies continuously from a first distance value increases a second, larger distance value.

In the context of this description, the surface of the carrier screen on which paper is deposited is regarded as the upper screen surface, the opposite screen surface as the lower screen surface, so that the statements "above the screen surface" or "below the screen surface" have a clear meaning ,

The distance values are taken from the Sieboberfläche upwards, ie in the direction of the deposited paper, positive, in the opposite direction negative. It is particularly advantageously provided that the first distance value of the stepless rise area extends downwards from the sieve surface, ie is negative, and that the second distance value extends upward from the sieve surface, ie is positive. The gray line produced in papermaking then shows a gradual gray gradient when viewed through transparency, ranging from gray values lighter than the gray value of the banknote paper surrounding the watermark to gray values darker than the gray value of the banknote paper.

However, the increase may also extend from an amount that is greater in magnitude to a smaller negative value, or from an amount that is smaller in size to a larger positive value in terms of amount, so that the increase range is completely below or above the sieve surface. The generated gray shading lines then show a gray gradient in transmitted light, the gray values of which, relative to the surrounding banknote paper, range from very dark to less dark and / or from very light to less bright.

erfüllen, wobei Δa = |a₂ - a₁| der Unterschied der Abstandswerte ist und amean =½ (|a₁| + |a₂|) den betragsmäßig mittleren Abstand darstellt. In diesem Fall beträgt die Abstandsänderung durch den Anstieg mindestens die Hälfte des mittleren absoluten Abstands von der Sieboberfläche, so dass eine Grauverlaufslinie mit kontrastreichem Erscheinungsbild resultiert.In any case, it is provided with particular advantage that the first and second distance value the relationship $$\mathrm{.DELTA.a}>\mathrm{½}*{\mathrm{a}}_{\mathrm{mean}}$$

satisfy, where Δa = | a ₂ - a ₁ | the difference of the distance values is and amean = ½ (| a ₁ | + | a ₂ |) represents the mean distance. In this case, the change in the distance by the increase is at least half of the average absolute distance from the screen surface, so that a gray-color line with a high-contrast appearance results.

The line-shaped motif element advantageously has a width of less than 0.6 mm, preferably less than 0.5 mm, particularly preferably less than 0.4 mm. Further, the length of the line-shaped motif element is advantageously more than 5 times, in particular more than 10 times as large as the width of the line-shaped motif element. With particular advantage, all line-shaped motif elements of the watermark insert fulfill the specified size specifications.

A particularly clearly defined appearance results when each rising area extending along the length of a motif element is more than 5 times, in particular more than 10 times, the width of the motif element, and / or extending along the width of a motif element Rise Area occupies the entire width of the creative element.

The line-shaped motif elements can be straight, but also curved, in particular be formed wavy. In advantageous embodiments, the plastic watermark insert contains a plurality of said line-shaped motif elements, which are arranged in the form of a geometric pattern, a barcode, a lettering or guilloches.

In one development of the invention, the plastic watermark insert in addition to one or more of the above-mentioned line-shaped motif elements further comprises a flatly extended relief area for generating a gradient watermark. The areal extensive relief area has in each direction a dimension of 5 mm or more, in particular of 10 mm or more. At least one of said line-shaped motif elements may be at least partially along the outline of the surface extend extended relief area and thus emphasize the generated by this history watermark stronger.

In an advantageous embodiment, the watermark insert is an injection molding insert. The injection molding insert is expediently formed from a hydrophobic plastic, for example from polyoxymethylene. To reduce wear during operation, the plastic may be added with wear-reducing additives.

Although the injection molding process for making the watermark insert is presently preferred, the watermark insert may also be made by deep drawing or hot stamping. In all manufacturing methods, a separate watermark insert can first be produced and perforated, and the separately produced watermark insert then connected to the carrier screen, in particular welded or glued. Alternatively, for example, first of all a plastic plate can be inserted into the carrier screen, and a watermark insert can be produced from the plastic plate used in the deep-drawing process or in the hot stamping process. In a subsequent method step, the watermark insert integrated in the carrier screen is then perforated, optionally together with the carrier screen. When using a deep-drawing process, an already pre-perforated plastic plate can also be used so that the subsequent perforating step can be dispensed with. Finally, the watermark insert can be injected with a corresponding tool shape directly into a cut-out portion of the mesh, so that a particularly intimate connection with the mesh arises. The dewatering screen may also have a plastic overmold or plastic backshell that connects the watermark insert to the carrier screen.

The watermark insert is preferably arranged in a cut-out region of the carrier screen and connected thereto only in a preferably serrated edge region. For this purpose, for example, by means of a laser cutting device at the location of the screen mesh, on which the watermark insert is provided, a recess can be produced which is slightly smaller, for example 1/10 mm smaller than the desired shape of the watermark insert. The edge region can be designed in particular in the form of a pattern, preferably in a serrated form. In this cut-out portion of the watermark insert can be inserted or preferably injected, as described above.

The support screen advantageously comprises a screen fabric with at least one system of interwoven, longitudinally extending warp threads and weft threads extending transversely thereto, the screen fabric advantageously comprising either a metal fabric, in particular a bronze fabric, a metal-plastic mixed fabric, in particular a bronze plastic Mixed fabric, or contains a pure plastic fabric.

Further, the watermark insert preferably has a plurality of perforations that ensure dewatering in papermaking. The dimensions of these drainage perforations are chosen so small that they do not adhere to fibers during papermaking. Typical perforation diameters are between 100 μm and a few 100 μm, for example about 500 μm. The perforations preferably taper towards the upper design surface of the watermark insert.

• ein bei der Papierherstellung zu erzeugendes Wasserzeichen vorgegeben wird, das als Motivbestandteil zumindest eine Grauverlaufslinie mit einer Breite von weniger als 1,0 mm enthält, die entlang ihrer Länge oder Breite einen stufenlosen Grauverlauf aufweist,
• ein Trägersieb mit einer Sieboberfläche für die Papieranlagerung bereitgestellt wird,
• ein Wasserzeicheneinsatz mit zumindest einem linienförmigen Motivelement mit einer Breite von weniger als 1,0 mm im Spritzgussverfahren in das Trägersieb eingespritzt wird, wobei das linienförmige Motivelement entlang seiner Länge oder Breite mit einem stufenlosen Anstiegsbereich erzeugt wird, in dem der Abstand zur Sieboberfläche stufenlos von einem ersten Abstandswert zu einem zweiten, größeren Abstandswert ansteigt, und
• der Wasserzeicheneinsatz durch Einwirkung von Laserstrahlung mit Entwässerungsperforationen versehen wird.

The invention also includes a process for making a dewatering screen for the production of paper with a watermark, in which

• a watermark to be produced in papermaking is provided which contains as a motif component at least one gray-line with a width of less than 1.0 mm, which has a stepless gray course along its length or width,
• a support screen is provided with a screen surface for paper attachment,
• a watermark insert is injected with at least one line-shaped motif element with a width of less than 1.0 mm by injection molding in the carrier screen, wherein the line-shaped motif element along its length or width is generated with a stepless rise area in which the distance to the screen surface stepless from a first distance value increases to a second, larger distance value, and
• the watermark insert is provided with drainage perforations by the action of laser radiation.

Preferably, in the method, the carrier screen is cut out in the region of the watermark to be generated, and the watermark insert is injected in the cut-out region of the carrier screen. Alternatively, the watermark insert can also be manufactured and perforated as a separate watermark insert, and welded or glued to the carrier screen.

Further embodiments and advantages of the invention will be explained below with reference to the figures, in the representation thereof to a scale and proportioned reproduction has been omitted in order to increase the clarity.

Fig. 1

in schematischer Darstellung das Erscheinungsbild einer Banknote mit einem Wasserzeichen mit mehreren Graustufenlinien im Durchlicht,

Fig. 2

einen Querschnitt durch die Banknote im Bereich einer der ersten Graustufenlinien entlang der Linie II-II von Fig. 1,

Fig. 3

einen Querschnitt durch die Banknote quer zu den zweiten Graustufenlinien entlang der Linie III-III von Fig. 1,

Fig. 4

eine schematische Darstellung eines erfindungsgemäßen Entwässerungssiebs, das zur Erzeugung von Wasserzeichen mit Grauverlaufslinien eingesetzt wird,

Fig. 5

einen Ausschnitt eines spritzgegossenen Wasserzeicheneinsatzes, der der Erzeugung der zweiten Grauverlaufslinien der Fig. 1 dient,

Fig. 6

einen Wasserzeicheneinsatz mit einem linienförmigen Motivelement, das mehrere Bereiche stufenlosen Anstiegs aufweist,

Fig. 7

einen Wasserzeicheneinsatz eines erfindungsgemäßen Entwässerungssiebs mit weiteren Arten linienförmiger Motivelemente, und

Fig. 8, 9

zwei komplexere Wasserzeichengestaltungen, bei denen die Grauverlaufslinien mit anderen, von herkömmlichen Wasserzeichengestaltungen bekannten Designelementen kombiniert sind.

Show it:

Fig. 1

schematic representation of the appearance of a banknote with a watermark with several gray scale lines in transmitted light,

Fig. 2

a cross section through the banknote in the region of one of the first gray scale lines along the line II-II of Fig. 1 .

Fig. 3

a cross section through the banknote transverse to the second gray scale lines along the line III-III of Fig. 1 .

Fig. 4

a schematic representation of a dewatering screen according to the invention, which is used to generate watermarks with gray lines,

Fig. 5

a section of an injection-molded watermark insert, the generation of the second Grauverlaufslinien the Fig. 1 serves,

Fig. 6

a watermark insert with a line-shaped motif element that has multiple areas of continuous increase,

Fig. 7

a watermark insert of a dewatering screen according to the invention with further types of line-shaped motif elements, and

Fig. 8, 9

two more complex watermark designs in which the gray lines are combined with other design elements known from conventional watermark designs.

The invention will now be explained using the example of watermarks for banknotes. FIGS. 1 to 3 show a schematic representation of a banknote 10, in the paper substrate 12, a watermark with first and second gray scale lines 14,16 were introduced with a continuous gray gradient. Fig.1 shows the appearance of the banknote in transmitted light, Fig. 2 a cross section through the banknote in the region of one of the first gray scale lines 14 along the line II-II of Fig. 1, and Fig. 3 a cross section through the banknote transverse to the second gray scale lines 16 along the line III-III of Fig.1 ,

When viewed in transmitted light, for example against daylight or a bright lamp, banknote paper is not completely opaque in the unprinted areas, but somewhat translucent and therefore appears with a certain gray value 12-M, the in Fig. 1 is indicated by a hatch of medium density.

The first gray shading lines 14 of the watermark have a width of only 0.6 mm and, in the transmitted light along their longitudinal direction, show a stepless gray progression, which ranges from a very light gray value to a very dark gray value. For graphic reasons, in reality the continuous gray gradient in Fig. 1 illustrated by a plurality of discrete hatching steps, where a low hatch density or white indicates a light gray value and a high hatch density or black indicates a dark gray value. As in Fig. 1 shown, the gray values of the gray course line are sufficient 14 of gray values 14-H which are lighter than the gray value 12-M of the banknote paper, to gray values 14-D which are darker than the gray value 12-M of the banknote paper.

The second gray course lines 16 have a width of 1.0 mm and, in the transmitted light along their transverse direction, that is to say their width, show a stepless gray progression, which ranges from a very light gray value to a very dark gray value. Here, too, for illustrative reasons, the gray gradient in reality is illustrated by a plurality of discrete hatch steps, the gray values of the gray line of gray values 16-H, which are lighter than the gray value 12-M of the banknote paper, reaching gray values 16-D, the darker ones when the gray value is 12-M of the banknote paper.

To illustrate the different paper thicknesses in the region of the gray course lines 14,16 show the FIGS. 2 and 3 Cross sections along the line II-II and III-III of Fig.1 , The nominal thickness of the banknote paper 12 outside the gray course lines 14, 16 is designated by So.

As in Fig. 2 1, the first gray-color lines 14 consist of a single rise area, in which the paper thickness increases continuously along the longitudinal direction of the line from a low value S _H , which produces a bright gray value 14-H in the case of see-through viewing, to a higher value S _D Transparency creates a darker gray value 14-D. In the transverse direction of the gray course lines 14, the paper thickness is constant. Since, in the exemplary embodiment shown, S _H <S ₀ <S _D , the light gray value 14-H is lighter and the dark gray value 14-D is darker than the average gray value 12-M of the banknote paper.

Also, the second gray course lines 16 each consist of a single rise area, in which, however, the paper thickness continuously increases along the transverse direction of the lines from a low value S _H <So to a higher value S _D > So. In the longitudinal direction of the gray progression lines 16, the paper thickness is constant, so that in total the above-described gray pattern results in transmitted light.

With conventional round watermarks or electrotype watermarks, such narrow lines can not be generated with a stepless gray gradient. In order to produce watermarks with gray lines of the type described, according to the invention in Fig. 4 schematically shown in cross-section drainage sieve 40 used.

The dewatering screen 40 comprises a carrier screen 42 with a screen fabric 44, which is cut out in a partial region 50. The height level of the paper facing surface of the support wire is in Fig. 4 indicated by the reference numeral 52. During papermaking, paper is deposited on the screen fabric 44 whose nominal thickness after drying with So ( FIGS. 2 and 3 ) referred to as.

The screen fabric 44 has at least one system of interwoven, longitudinally extending warp threads 46 and weft threads 48 extending transversely thereto. In the context of the present invention, the screen fabric may for example contain a metal fabric, in particular a bronze fabric, a metal-plastic mixed fabric, in particular a bronze-plastic blended fabric, or even a pure plastic fabric. The support screen 42 may include both a single-layer and a multi-layer mesh, with the simpler view being shown in the figures only single-layer mesh.

In the cut-out portion 50 of the mesh fabric 44, a plastic watermark insert 60 is arranged, which is connected at its edge to the mesh fabric 44. The connection can in principle be made in many ways, for example by a plastic encapsulation or back injection, with the aid of a plurality along the edge arranged fastening knobs, or by welding or gluing.

In the exemplary embodiment, a further variant is realized in which the plastic watermark insert 60 is an injection-molded element which is injected directly into the cut-out portion 50 of the screen fabric 44 with a corresponding tool shape and thereby enters into a particularly intimate connection with the screen fabric.

The injection-molded watermark insert 60 has a line-shaped motif element 62 with a width of 0.6 mm, which consists of a single rise area in which the distance to the screen surface 52 along its longitudinal direction L steplessly from a first distance value a _{1 to} right end 64-1 of the motif element 62 increases to a second, larger distance value a ₂ at the left end 64-2 of the motif element 62. As explained above, the distances from the screen surface 52 upwards, ie in the direction of the paper to be deposited, positive, distances from the screen surface 52 are calculated negative downwards.

In the embodiment of Fig. 4 is the distance value a ₂ positive, the left end 64-2 is thus above the sieve surface 52, and the distance value a ₁ is negative, so that the right end 64-1 is below the sieve surface 52. In papermaking, the right end 64-1 of the motif element 62 creates a region of increased paper thickness S _D > So, the left end 64-2 creates a region of reduced paper thickness S _H <So, and the stepless one Rise region between the two ends 64-1, 64-2 produces a continuously increasing from S _H to S _D paper thickness, so that a total of a gray line 14 with the at Fig. 1 described appearance arises.

The watermark insert 60 is further provided with a plurality of only indicated in the figure perforations 58 to ensure drainage in papermaking also in the field of watermark insert. The diameter of the perforations 58 is chosen so small that they do not adhere to fibers in paper production. Typical perforation diameters are between 100 μm and a few 100 μm, for example about 500 μm.

Fig. 5 shows a section of an injection-molded watermark insert 70, the generation of the Grauverlaufslinien 16 of Fig. 1 serves. For ease of illustration, the support screen and the perforations are omitted in this and the following figures. The watermark insert 70 may also be integral with the watermark insert 60 of the Fig. 4 be educated. The watermark insert 70 includes three line-shaped motif elements 72 with a width of 1.0 mm, the longitudinal direction in the representation of Fig. 5 is perpendicular to the paper plane. Each motif element 72 consists of a single rise area in which the distance to the screen surface 52 along its transverse direction Q increases steplessly from a first distance value a ₁ at a longitudinal edge of the motif element to a second, larger distance value a ₂ at the opposite longitudinal edge of the motif element. In papermaking, the longitudinal edge having the negative distance a ₁ produces a region of increased paper thickness S _D > So, the longitudinal edge having the positive distance a ₂ produces a region of reduced paper thickness S _H <So and the stepless rise region between the two longitudinal edges one stepless along the width from S _H to S _D increasing paper thickness, so that the total gray line 16 with the at Fig. 1 arise appearance described.

The line-shaped motif elements can also have several regions of stepless rise and thus produce gray-color lines with a more complex gray gradient. In the embodiment of Fig. 6 The watermark insert 80 includes, for example, a line-shaped motif element 82 having a width of 0.4 mm, which has four stepless rise regions 84-1 to 84-4 along its longitudinal direction L. As in Fig. 6 4, the distance in the regions 84-1 and 84-4 respectively increases from a negative value to the outside to the level of the sieve surface 52, ie to a distance value a = 0, while in the regions 84-2 and 84-3 increases from a negative value to the same positive value in the middle of the line. Overall, in papermaking, motif element 82 produces a gray gradient line having a neutral / dark / light / dark / neutral brightness sequence, where "neutral" denotes the brightness of the surrounding banknote paper. The watermark insert 80 of the Fig. 6 also illustrates that the increase in the rise areas does not have to be linear.

Furthermore, the increase does not necessarily have to run from a negative to a positive distance value, but instead may, for example, also run from a value that is greater in magnitude to a smaller negative value, as in the case of the linear motif element 86 of the left part of FIG Fig. 7 shown. The motif element 86 generates a gray course line in papermaking whose gray values range from a very dark to a less dark image impression. Since the entire motif element 86 is below the screen surface 52, the entire generated gray-color line appears darker than the surrounding banknote paper. Similarly, the increase may be from a smaller amount to a smaller amount greater positive value, as in the line-shaped motif element 88 of the right part of Fig. 7 shown. The motif element 88 produces a gray course line in papermaking whose gray values range from a less bright to a very bright image impression. The entire generated gray line appears brighter than the surrounding banknote paper because the entire motif element 88 is above the screen surface 52. Of course, the increase can also start or end at the height of the sieve surface 52 at a distance value a = 0, as already in FIG Fig. 6 illustrated.

Irrespective of the sign of the two distance values, the first and second distance values of a rise region advantageously satisfy the relationship Δa> ½ * a _mean , where Δa = | a ₂ -a ₁ | the difference of the distance values is and amean = ½ (| a ₁ + | a ₂ |) represents the median distance. In this case, the change in the distance due to the increase is at least half of the average absolute distance from the screen surface 52, so that in each case a gray gradient with a high-contrast appearance results. If a gray gradient line contains a plurality of stepless rise areas, then the said relationship is advantageously fulfilled in each rise area.

Of course, the watermarks to be generated can have more than one gray-color line and, in addition to gray-color lines, also contain other design elements known from conventional watermark designs. The Grauverlaufslinien must also not be rectilinear, but may be curved, in particular wavy ausbildet, and for example, form a lettering or a guilloche pattern, or even completely or partially follow the outline of a conventional history watermark. For example only are in the FIGS. 8 and 9 two more complex Watermark designs shown with gray lines. Because of the above explanations, it will be apparent to those skilled in the art how to design a corresponding watermark insert to produce these watermarks.

Fig. 8 5 shows a plan view of a banknote paper 20 with a watermark 22, the four arranged in a square gray course lines 14 after Fig.1 with a width of only 0.6 mm. Inside the square, the value "10" is arranged in the form of a highlight watermark 24 appearing very bright in transmitted light. In addition to the already described line-shaped motif elements, two motif elements in the form of the numbers "1" and "0" which project significantly beyond the screen surface 52 are provided on the associated watermark insert, which contain no rise area and are therefore regarded as conventional design elements for the present description.

In the embodiment of the Fig. 9 The watermark 30 contains a gray course line 14 and a gray curve line 16 Fig. 1 that are combined with a conventional history watermark 32. In addition to the already described line-shaped motif elements 62 and 72, the associated watermark insert also contains an areal extended relief area for generating the gradient watermark 32. At least one gray-shaded line can also extend wholly or partially along the outline of the gradient watermark 32 and thereby accentuate it more strongly.

LIST OF REFERENCE NUMBERS

10

bill

12

paper substrate

12-M

gray value

14

first grayscale lines

14-H, 14-D

light or dark gray values

16

second grayscale lines

16-H, 16-D

light or dark gray values

20

Banknote paper

22

watermark

24

Highlight watermarks

30

watermark

32

History watermark

40

dewatering

42

support screen

44

mesh

46

warp

48

wefts

50

cut out section

52

Height level sieve surface

58

perforations

60

Watermark use

62

linear motif element

64-1, 64-2

right or left end

70

Watermark use

72

linear motif element

80

Watermark use

82

linear motif element

84-1 to 84-4

stepless rise areas

86

linear motif element

88

linear motif element

L

longitudinal direction

Q

transversely

a ₁

first distance value

a ₂

second distance value

Claims (17)

Drainage screen for the production of paper with a watermark, characterized in that the watermark to be produced in papermaking contains, as a motif constituent, at least one gray-line with a width of less than 1.0 mm, which has a stepless gray course along its length or width, - The dewatering screen has a carrier screen with a Sieboberfläche on which paper is deposited, as well as arranged in a portion of the support screen perforated plastic watermark insert, wherein - The plastic watermark insert for generating the Grauverlaufslinie (s) at least one line-shaped motif element with a width of less than 1.0 mm, along its length or width has a stepless rise area in which the distance from the screen surface steplessly from a first distance value increases to a second, larger distance value. A drainage screen according to claim 1, characterized in that the first distance value of the stepless rise area extends downwardly from the screen surface and the second distance value extends upward from the screen surface. Entwässerungssieb according to claim 1 or 2, characterized in that the first and second distance value, the relationship .DELTA.a> ½ * a _mean satisfy, where Δa = | a ₂ - a ₁ | the difference of the distance values is and a _me-an = ½ (| a ₁ | + | a ₂ |) represents the mean distance in terms of magnitude. Entwässerungssieb according to at least one of claims 1 to 3, characterized in that the line-shaped motif element has a width of less than 0.6 mm, preferably less than 0.5 mm, more preferably less than 0.4 mm. Drainage screen according to at least one of claims 1 to 4, characterized in that the line-shaped motif element has a length and a width, wherein the length is more than 5 times, in particular more than 10 times as large as the width. Dewatering screen according to at least one of claims 1 to 5, characterized in that each rising along the length of a motif element rising area more than 5 times, in particular more than 10 times as large as the width of the motif element, and / or that each along the width of a motif element extending slope area occupies the entire width of the motif element. Entwässerungssieb according to at least one of claims 1 to 6, characterized in that said line-shaped motif elements are rectilinear or curved, in particular corrugated formed. Drainage screen according to at least one of claims 1 to 7, characterized in that the plastic watermark insert contains a plurality of said line-shaped motif elements, which are arranged in the form of a geometric pattern, a bar code, a lettering or guilloches. Entwässerungssieb according to at least one of claims 1 to 8, characterized in that the plastic watermark insert in addition to one or more of said line-shaped motif elements contains a flat-extended relief area for generating a history watermark. Entwässerungssieb according to claim 9, characterized in that one of said line-shaped motif elements extends at least partially along the outline of the flatly extended relief area. Entwässerungssieb according to at least one of claims 1 to 10, characterized in that the watermark insert is an injection molding insert. Entwässerungssieb according to at least one of claims 1 to 11, characterized in that the dewatering screen has a plastic encapsulation or plastic injection-back, which connects the watermark insert with the support screen. Drainage screen according to at least one of claims 1 to 12, characterized in that the watermark insert is arranged in a cut-out region of the carrier screen and is connected to it only in a preferably serrated edge region. Dewatering screen according to at least one of claims 1 to 13, characterized in that the carrier screen has a screen fabric with at least one system of interwoven, longitudinally extending warp threads and weft threads extending transversely thereto, wherein the screen fabric advantageously either a metal fabric, in particular a Bronze fabric containing a metal-plastic blended fabric, in particular a bronze-plastic blended fabric, or contains a pure plastic fabric. Dewatering screen according to at least one of claims 1 to 14, characterized in that the watermark insert has a plurality of perforations, the dimensions of which are so small that they do not adhere to fibers during papermaking. Process for producing a dewatering screen for the production of paper with a watermark, in which a watermark to be produced in papermaking is provided, which as motif component contains at least one gray-line with a width of less than 1.0 mm, which has a stepless gray course along its length or width, a support screen is provided with a screen surface for paper attachment, - A watermark insert is injected with at least one line-shaped motif element with a width of less than 1.0 mm by injection molding in the carrier, wherein the line-shaped motif element along its length or width is generated with a stepless rise area in which the distance to the screen surface stepless from a first distance value increases to a second, larger distance value, and - The watermark insert is provided by the action of laser radiation with drainage perforations. A method according to claim 16, characterized in that the carrier screen is cut out in the region of the watermark to be generated, and the watermark insert is injected in the cut-out region of the carrier screen.

Images