removable watermark for craft paper form.

Abstract

Removable watermark device for traditional manual paper mold. The device is a fabric, carrying the excess thickness of the watermark, to be stretched between a screen and a cover. This simple device allows the same mold to sequentially produce series of sheets of paper with different watermarks. Figure for the abstract: Figure 5

Description

Title of the invention: removable watermark for handmade paper form.

[0001] The present invention relates to the hand-made manufacture of sheets of paper incorporating watermarks. Technical field of the invention

[0002] The present invention relates to the production of sheets of paper by hand using a traditional form (1) in which clear watermarks are integrated, i.e. patterns appearing clearly when viewed through transparency of the sheets of paper. Technological background

[0003] Handmade paper sheets, when made by hand, are made by dipping a paper former into a vat of cellulose fibers suspended in water.

[0004] By removing this form horizontally from the water, it "moulds" the cellulose fibres into the form of a sheet while draining the water through the sieve (2). The cover (3) allows the fibres to be held on the sieve and forms the regular edges of the future sheet of paper. After drawing, the cover (3) is removed to allow the sheet to be laid on a sheet of damp felt. It will then be pressed and then dried.

[0005] Thus formed, the sheets have a uniform thickness and therefore a uniform transparent appearance. Because when drawing - leaving the form (1) of water - the cellulose fibers are uniformly distributed over the entire surface of the sieve (2).

[0006] However, if the screen has areas of excess thickness on its surface, the number of fibers will then be locally lower. This reduced local number of fibers will give the sheets lighter areas through transparency. Arranged in a pattern, this will form a watermark.

[0007] Traditionally, to create these watermarks, the extra thicknesses forming the patterns are made with metal wires sewn onto the screen (2).

[0008] For several years, solutions using rapid prototyping tools have been considered for the production of security watermarks.

[0009] Both the traditional solution and these new solutions require permanent modification of the paper forms. However, these forms represent a significant investment for a small artisanal production. Hence the idea, described here, of a removable extra thickness device (i.e. watermark) allowing, with the same form (1), to the papermaker, the production of series of sheets of paper with different watermarks. Presentation of the invention

[0010] To allow simple installation and removal of the excess thickness forming the watermark, the invention consists in that the excess thickness of the watermark is fixed on a fabric or a metal mesh independent of the shape and adjustable on it.

[0011] This fabric or cloth is positioned on the draining screen and in fact constitutes a first and additional filtration stage.

[0012] The thin metal fabric or cloth can be inserted between the sieve (2) and the cover (3).

[0013] The fabric or metal mesh can be folded over the edges of the screen and kept taut by a tensioner system on the back of the screen.

[0014] In addition, the folded sides of the fabric or wire mesh may be provided with a rigid part to prevent the formation of folds during tension.

[0015] The excess thickness, forming the watermark (4), is integral with the fabric or canvas and can be produced by a means of rapid prototyping of material deposition by successive layers. Brief description of the drawings

[0016] In order to better understand the invention described, some figures are provided in the appendix as purely illustrative and non-limiting examples: • [Fig. 1] shows a traditional paper form • [Fig.2] shows a section of the assembly covered on a sieve of a form traditional. • [Fig.3] shows an example of the production of a removable fabric or canvas bearing a watermark • [Fig.4] shows a section of one of the edges of an example of the construction of the removable fabric or canvas with tensioner attachment rope and rigid reinforcement tube • [Fig.5] shows an exploded view of an example of a covered, canvas, sieve assembly • [Fig.6] shows a back side view of an example of a fabric or canvas assembly stretched over the screen. Description of the embodiments

[0017] Figures 1 and 2 show a typical structure of a manual paper form.

[0018] To easily position and remove on the sieve (2) of this shape an excess thickness (4) which will form a watermark in the sheets produced, this excess thickness (4) is produced on an independent fabric (6) whose shape is for example given in the [Fig.3].

[0019] This fabric carrying the excess thickness of the watermark is then positioned on the sieve under the cover see [Fig.5].

[0020] The edges of the fabric are folded under the sieve (2) and kept taut by elastic hook cables (7) see [Fig.6]. In the case shown of a rectangular shape, an elastic cable joins the two long edges of the fabric and another cable the two short edges.

[0021] In order to avoid creases in the fabric (6) when it is stretched, a hem is made on each side using a seam (11). An aluminum tube (8) is threaded into this sewn hem. In this tube (8) a cord (9) forms a loop allowing an elastic cable (7) to be hooked / unhooked. See [Fig.4].

[0022] Thus mounted, the removable fabric (5) carrying the excess thickness of the watermark is fixed, without creases and well stretched on the draining screen.

[0023] The fabric being of low thickness, it does not hinder the placing or removal of the cover (3) on the sieve (2).

[0024] In fact, it constitutes an additional filtration stage for the sieve. But if the mesh of the fabric has been well chosen, this does not constitute a brake on the drainage of the sheet of paper in formation. In addition, the elastic cables (7) holding the fabric passing under the sieve (2) [Fig.6], they do not constitute a brake on drainage either.

[0025] Laying the sheet on its wet felt can also be carried out conventionally without the removable fabric hindering the operation.

[0026] The removable fabric bearing the excess thickness (5) can thus remain in place on the screen throughout the production of the sheets bearing this watermark. At the end of the production of the series of sheets, the fabric (5) can be removed from the form and stored for later use, while the form can resume the production of the sheet without the watermark or with another removable fabric bearing another watermark.

[0027] The excess thickness (4) forming the watermark is in this embodiment directly printed on the fabric (6) using a PLA filament deposition 3D printer. For this purpose, the nylon fabric (6) is glued to the plate of the 3D printer. After printing the first layer of plastic, printing is paused, so that the first layer can be fixed to the fabric by passing an iron over it. Once this first layer is fixed, printing of the following layers can be continued normally.

[0028] The print height, therefore the extra thickness forming the watermark, depends on the weight of the sheets of paper that you wish to produce. List of reference signs

[0029] 1: manual & traditional paper form 2: frame / draining sieve 3: covered 4: extra thickness for forming a watermark 5: Removable watermark device 6: fabric or canvas 7: elastic cable with hook or tensioner 8: rigid tube 9: cord 10: area of ​​the fabric covering the sieve 11: Hem sewing

Claims

Claims

1. Watermarking device for manual paper form characterized in that the excess thickness of the watermark is fixed on a fabric, or a metal mesh, independent of the form and adjustable on it.

2. Device according to claim 1 in which the fabric is folded over the edges of the screen and kept taut by a tensioner system on the back of the screen.

3. Device according to claims 1 and 2 in which the folded edges of the fabric are provided with a rigid part making it possible to avoid creases in the fabric when it is stretched.

4. Device according to claim 1 characterized by the production, directly on the fabric, of the excess thickness of the watermark by a means of rapid prototyping of material deposition by successive layers.

Images